Results 1 to 13 of 13
  1. #1
    Join Date
    Aug 2007

    Mossberg 930 SPX Review

    The 930 SPX is loaded with features that attracted me to it, and the price was a bargain compared to what a comparable package would cost from Remington or Benelli, which are the other two tactical shotguns that I have experience with and was considering for a semiauto shotgun purchase.
    The Mossberg 930 SPX is a 12 gauge semiautomatic gas-operated shotgun. There are two gas ports that drive a piston that surrounds the magazine tube beneath the barrel. This moves a pusher with two short steel action bars that in turn push the bolt carrier. The gas system is said to be self-regulating, meaning that it is intended to be capable of digesting virtually any ammunition type outside of the minimally-powered LTL rounds. There is no gas seal ring as on the 1187. The shotgun is able to chamber 2.75" and 3" shells. With 2.75" rounds the mag tube will hold seven rounds fully charged. With 3" shells this capacity drops to six. That totals out to either eight or seven total rounds, respectively.
    The 930 SPX model is quite different from the 930 Home Defense, and the differences are immediately noticeable. In spite of these, there is a lot of commonality in the parts of the SPX, the Home Defense, and other recreational 930 variants. Mossberg took the 930 receiver and synthetic stocks, and added the 18.5 Home Defense barrel, LPA ghost rings sights, and a Picatinny rail to produce the SPX.
    The shotgun is very light. This is due to the aluminum receiver used, although the barrel and chamber are steel. The weight coupled with the short 18.5” barrel make the 930 extremely maneuverable. It feels quite different from my 590A1 with its 20” barrel. I would imagine that with a shorter LOP stock it would be very handy in the restrictive indoor setting or if you wear a PC, or even if you are wearing a heavy coat. Like other Mossbergs, it comes with the stock spacers that will allow the angle of the stock to be changed. The barrel and receiver are finished in a flat matte black finish, and the stocks are black synthetic.

    The magazine extension that allows 8 rounds to be loaded in the SPX is flush with the end of the barrel. It is produced by Choate, and has the floating plastic button end-cap. The nut area of the extension is well knurled. There is not a detent that secures the extension to the barrel band although the rear edge of the extension is set up to do so. For some reason, Mossberg neglected to install some form of forward sling attachment point. I intend on using a 590 sling point that installs between the extension and the barrel ring. Even fully loaded at seven rounds in the mag and with the steel extension out front, the shotgun still balances well for me, and did not feel nose heavy.
    When loading the shotgun, I typically leave the tube downloaded by one round, chamber empty, with the hammer down and the safety off; most will recognize this as cruiser ready.
    In the event that you would like to make a chambered SPX cruiser ready the procedure is basically the same as on the 870 or other more widely used shotguns. Engage the safety, place the butt forward of the right hip, and place the left hand under the receiver so that you can push your left thumb into the loading port. Using the tip of the left thumb, push the ready round forward so that it stays forward of the shell stops. Now pull the bolt handle to the rear with the right hand extracting the chambered round. Allowing the round to be ejected, visually inspect the chamber and elevator to ensure that there is no live round about to be chambered, or remaining in the chamber. You can now allow the bolt to return to battery while keeping the left thumb holding the ready round in the mag tube and behind the shell stops so that it is not chambered. You may now remove your left thumb from the loading port and resume holding the forearm with again. Once this is completed, you can double check the chamber by pulling the bolt slightly to the rear so that you can visually verify that there is no round chambered. With the chamber empty, you can disengage the safety and pull the trigger. The shotgun is now in cruiser ready. This procedure can also be used as the initial procedure when completely unloading the shotgun (the remainder of this procedure is detailed below), just as on the 870 so that a chambered round can be safely removed and the mag tube cleared without cycling each round through the chamber.

    One of the best features of the SPX is the sights. This is among the best of the ghost ring sight units that I’ve used, certainly for a stock direct from the factory shotgun. Mossberg chose the LPA ghost ring sights from Italy and hit the ball out of the park as far as I’m concerned. The front is described as M16 style, and is a raised tower type unit that appears to be welded onto the barrel at the muzzle, and has protective ears and a red fiber optic insert. Honestly, I’m not a big fan of fiber optic sights, and I’ll switch this out for a tritium unit. Lots of people love the fiber optic sights, and my dealer said I should keep them when I mentioned wanting to change them. The fiber optic requires too much light for me, and worse requires it around you in order to be seen. I would prefer the self-luminous tritium and the big white circle around the vial to be able to pick out the front sight blade in lower light levels where I am not in a lot of light.

    The rear sight is a detachable ghost ring unit, again with thick protective ears to either side. It is very sturdily constructed and sits on the Picatinny rail mounted to the top of the receiver. The sight is adjustable for both windage and elevation using a small standard screwdriver. The elevation is adjusted forward of the rear aperture and is very clearly marked “UP.” The windage is adjusted by a cross screw that drives the aperture left and right similar to the M16 rear sight. It too is marked; an “R” with direction arrow is placed above the adjustment screw on the right side of the assembly. There is also a witness mark and adjustment scale at the rear aperture for visual reference when zeroing, and I suppose this would be handy if you ever needed to move the sight to make sure you could return to BZO. I think the markings might be a little small for indexing them with your own witness marks as is often done with the M16 or AR15 type sight. The markings are very clearly laid out in a high contrast white. The adjustments are positive, with audible and tactile clicks. It does require a conscious effort to move the sight aperture, and you will certainly notice when you are doing so. The sight is removable, and uses a captured thumbnut on the left side of the assembly. It has a slot for using a flat-bladed driver to secure or loosen it. Unless you really intend on taking the sight off and putting it back on a lot, I would LocTite the thing.

    The sight picture is very clear, and gives the impression of sighting through goal posts. The fiber optic picks up the ambient light, but as I stated I’m looking for just a little more. The ghost ring aperture is substantial enough to not be dainty and easily damaged, but not overly large so that it becomes self-defeating with too much obstruction or distraction.
    One nice feature of the LPA rear ghost ring is the counterbored apeture. This prevents glare from the rear sight when shooting in bright light.

    The Picatinny rail is mounted on the top of the receiver with 4 small screws. It appears to be in spec, with no problems mounting any of my Pic rail stuff that I had on hand. This is a very nice platform for optics if you chose to put one on the SPX.

    Working on around the receiver, there is a typical Mossberg tang-mounted safety. While the position is great for conventional stocks, the rumored after-market pistol grip unit might make this difficult. ***UPDATE: Choate advised that the PG stock for the 930 will be available by the end of February 2008.*** Regardless, the standard safety button is the plastic version. This will definitely be changed out for either the enlarged butterfly or Vang metal safety buttons.

    The charging handle is the typical pull-out type, with an oval bearing surface. On a tactical gun I would prefer this to be a little larger, along the lines of the squared Choate unit so that the handle can be manipulated from underneath the shotgun easily. ***UPDATE: The good people at Choate will be producing a 930 version and advised that they expected this to be released by the end of February 2008.*** The bolt locks positively to the rear on empty, and does not dislodge when the shotgun is given an aggressive series of bumps on the floor.
    The bolt release is well placed, and is substantial enough to be easily found by touch. The size allows for positive feel even through gloves. It is also used as a quick unload button by pushing the elevator up towards the bottom of the bolt and pushing the bolt release. This allows the ready shell in the mag tube to be released from the stops and removed from the loading port. By repeating this procedure, the mag tube can be emptied entirely through the loading port as opposed to clearing through the chamber.

    The magazine tube spring at this point is acceptable, although I would like to see the last round forced out with a little more authority. The follower is acceptable as well, and is a metal (steel?) cup-type. I was able to create a bind on it by intentionally using poor loading procedures. A quick vertical bump on the floor freed the follower and returned the rounds to the ready with the follower in battery. A non-binding hi-vis nylon follower will replace the stock unit soon.
    The trigger guard appears to be metal, which I am glad to see. The elevator is a solid flap, with a scalloped cut on the front edge. It moves freely, but I would like very much to see a cut made in the body of the elevator, so that a shell that either flies free of the shell stops or that does not get fully engaged upon loading can be pushed back into the mag tube with a tool.

    There is a cocking indicator inside the forward edge of the trigger guard. I guess this might benefit some, and would lend itself to verifying that the shotgun is in the semi-auto version of cruiser ready if you need that sort of thing.

    The stocks are about what I would expect for standard factory units. They retain the sporting look of the 930 recreational shotguns. The rear stock has an integral sling point along the bottom edge. I am not a fan of this. I would prefer a standard metal button. The recoil pad is very substantial. It is soft enough to slow down the shotgun, but not overly so. It is chamfered at the heel slightly, and my only complaint is that at the heel there is a slight gap. This looks like it is due to the recoil pad screw being just a little higher than it should be with this pad, and there is enough “slop” in the pad to allow it to pull away from the toe of the stock.

    The foreend is also of the sporting variety, and its lineage shows. The rear edge of the foreend overhangs the forward edge of the receiver. It is rather blocky along the bottom of the receiver, and in my opinion interferes slightly with rapid loading through the port. The bottom of the stock protrudes below the level of the receiver, and I would rather that part of the foreend either be removed or be scalloped/tapered back so that there is more clearance around the loading port. For whatever reason, there is also some very noticeable vertical movement in the rear of the foreend. ***UPDATE: I took the 930 completely apart to clean it. After reassembling the shotgun and really clamping down on the extension there is much less movement in the foreend. I would say that it is at an acceptable level. After adding a Wilson Combat vertical sling point this movement has been all but eliminated. But I still want it beveled.

    Finally, a comparison between the 590A1 barrel and the 930 SPX.

    Overall, I have been very impressed with the SPX. It provides a lot of extra features on a shotgun chassis that has already shown a high degree of reliability. So while the SPX variant is new, the 930 has been around for a while. It can often be found for around $500, which is a steal when you consider that the sights alone run about $200. The tactical features added to the basic sport model of shotgun make this a very competitive entry, and show that Mossberg made some good choices compared to the 500 and 590 shotguns, which lack the ability to increase or decrease magazine capacity. The ghost rings on the SPX are simpler and more robust than the factory set on my 590A1. I am very much looking forward to being able to start putting rounds downrange soon.
    I did get a chance to put a few rounds through it today. No problems with light loads (quail and trap loads), reduced recoil tac loads (Rem and Fed), up to full power Remington buck and Brenneke slugs. Didn't have time to pattern it, but I'm going to try to get around to that over the weekend.
    Last edited by m24shooter; 29 December 2007 at 09:38. Reason: Clarity and added details

  2. #2
    Join Date
    Aug 2007
    Some updates:
    I added the Wilson Combat vertical sling mount for the 870. Yes it works. It has a detent to keep the extension from backing out. The factory extension has the knurling for this detent, but there isn't one on the foreend. The material on the foreend is too shallow to properly rig a detent spring recess, so I just drilled it through to allow for some clearance of the detent ball as it gets pushed back by the extension knurling.
    First, the knurling:

    Then the parts together.

    Now the mount and extension assembled.

    And I also added a Streamlight M3/M6 base. I have a feeling that Mrs Shooter is going to get me a TLR.
    Here is the "front" showing the locking bar cut.

    And here is the back showing the three machine screws securing the clamping jaws.

    The mount is plastic, and this may not be the final version. I am not sure that I am comfortable with a plastic mount, or the clamping method of attachment. I am pretty sure that I will be using another one, but I'll give this a try.
    Forgot to add: Got the chance to put about 200 rounds downrange. Some quail and game loads, as well as more buck and slugs. Still going at it and doing fine. This shotgun is great!
    Last edited by m24shooter; 29 December 2007 at 09:25.

  3. #3
    Join Date
    Aug 2007

    I've had some time to put more rounds downrange, and the SPX is still going along just fine. It eats everything that I've put through it, and I'm still working though several buck loads to see which patterns best.

    I've added the following:
    -stock pouch since there is no sidesaddle ammo carrier yet

    -MagPul ladder cover on the exposed Pic rail because of some slight cheese grater issues

    -TLR light with remote switch and plate

    The TLR is an aluminum bodied LED tactical light that uses 2 of the common 3V 123 cells. It is pretty much a zero-maintenance unit that only requires the replacement of batteries. It is dust-, shock-, and waterproof.

    The lens is glass, and has a pretty tight blue-white beam with a substantial amount of peripheral illumination as well.

    Using the Streamlight M3/M5 mount for generic shotgun mag tubes, I positioned the light at the 3 o'clock position to keep my FOV clear.

    The TLR comes with a basic momentary and constant on rocker switch. To use the light on the SPX I had to add a means of remote operation.

    In order to use a remote switch I had to replace the stock switch and rear battery cover with a unit that would accept the remote switch coupling. This unit has half of the rocker arm of the standard switch and a socket for the tape switch. It allows for the standard momentary and constant on using the rocker arm. Replacing the standard battery cover with the remote unit was interesting. The clamping bar that secures the plate was rather tough to get back into place over the new remote switch unit. I don't know if there was more waterproofing gasket to deal with or what, but it took some work to get it shut again. A nice feature of the new plate was a rubber plug that rests in the remote switch socket when the tape switch is not used. When the tape switch is used, the plug (which is tethered) nests into the pivot on the rocker switch.

    I went with the remote switch for rifles. It is an 8" straight cord with a remote tape switch. The 8" length includes the angled piece that plugs into the lamp unit. The switch itself is about 3" long and has a hard base with the switch itself being centered in the base. The switch is much stiffer than SureFire models, and takes a more authoritative squeeze to activate.
    There are several mounting options provided with the switch. The unit can be secured using a two-sided adhesive strip to a smooth surface. There are also two small screws that can be drilled into the weapon, and there are two rail interface pieces that would allow the switch to fit on a length of rail. Two zipties are included to secure the cable. I went with the adhesive pad.

    Future plans include an optic, possible sight switch for tritium units, a metal safety, and the handguard trim around the loading port.

    Added the metal safety from Vang. It is somewhat teardrop shaped, with the larger end oriented to the rear. It is slightly taller than the factory plastic model, and has a more aggressive feel to it. It is now a very simple matter of simply flicking the thumb forward while shouldering to disengage the safety. I have the factory metal safety on a 590A1, and I may have to switch that out for one of these. A very nice version of a rather low profile part that makes a difference in the feel of the shotgun.

    Last edited by m24shooter; 4 January 2008 at 16:32.

  4. #4
    Join Date
    Aug 2007

    Updated review and status 20 Mar 08

    Still running the SPX. In the last few weeks I've made a few more adjustments and added some new parts. I've also been getting some feedback from some other SPX users.

    Reported Problems:

    It seems that there are a few problems that are occurring with some SPX models. In my opinion these are all gripes that should have been caught before the shotgun left the factory, and one seems to be an assembly error. So here are a few things to check when you get your SPX:
    1. Check the mag tube extension. I've seen one report of a user that had a dent in the mag tube that was causing the follower to bind up and thus not feed the rounds from the tube.
    2. Check the alignment of the front sight tower. There have been a few canted front sight towers.
    3. Check the front two screws on the Picatinny rail. Several people have had issues with these appearing to be over-torqued at the factory during installation. This has stripped out the threads in the receiver, leaving only the two rear screws holding the rear (where the receiver is thicker) of the rail on.
    Those are the problems that I'm aware of. There haven't been a lot of these, but the last two are two that I've seen more than one report of. I would say that I've seen probably 4 to 5 reports of each. I don't know of more than one of the first problem, and I don't know of anybody who has been unlucky enough to have all three. I've seen far more good reports on the SPX than bad by a huge margin. Mossberg has been handling the problems under warranty from what I've heard as well.

    As another point of information, it helps to clean the SPX well before you shoot it for the first time. Mossberg seems to on occasion have a lot of preservative or fouling in their shotguns in them, and some people have had issues with malfs due to not cleaning their new SPX shotguns. Additionally, your SPX may be ammunition sensitive at first. A lot of shooters have had problems using slower/lighter shot loadings cycling their new SPX. Using heavier (above 1300fps) loads at first and then transitioning down to lighter loads seems to work for those that had ammunition issues.
    I've had one stovepipe on some old (probably 10 years) low-brass WalMart light loads among all the different types that I've shot, and that has been the extent of ammo sensitivity on my SPX.

    The NOB:

    In terms of my shotgun, one of the big things I've added is The NOB, which is an enlarged bolt handle replacement. I've got a prototype unit that I'm testing for the manufacturer, and it is really working out well. I'll have a completely separate review of it up soon after I've fully rung it out. I'm doing my best to beat the snot out of it right now, and when I'm done I'll put the review up here.

    Update: Craig at Gun Connection is making The NOB again. You can reach him at:
    I have just gotten the updated version and I will be working this into the new update soon.

    Clearance Cut:

    Another change to the shotgun is the cutting of the foreend. I trimmed the rear overhang back from the loading port to allow easier access to the port. Right now I've got it cut back to a vertical edge, but I might have this tapered back some depending on how I like it. I can tell a difference in how the loading manipulation is more like other defensive shotguns without the long sporting-type foreend.

    Here it is before the cut:

    And here it is after:

    Switch Screws:

    I've also secured the Streamlight remote switch pad for the TLR with the supplied screws. I didn't think that the adhesive would hold up for long, and I was right. It separated when I was doing a lot of slug work, but it did hold up longer than I thought it would. A note of caution to anyone using the screws to mount the pad on a foreend: trim the points of the screws as needed so that the piston assembly can freely move. I did some test fitting to make sure that the screw points wouldn't interfere.

    Added 22 March 08:
    I've been asked a couple of times about the sling and how it is set up on my SPX. Here's the info:

    The sling is a Gear Sector GS-2P adjustable two point.

    It is attached to the stock with a Gear Sector Fixed Stock Adapter, which I don't think is available yet. It is ambidextrous and fits pretty much any fixed stock.
    ETA: I just checked with Jason and they are available at:

    The front is a SGT/Wilson side sling adapter from Brownells.

    Last edited by m24shooter; 11 November 2008 at 07:20.

  5. #5
    Join Date
    Aug 2007


    Since the last update I’ve tried several new items on the SPX. Among these are:
    Trijicon 4MOA Mini Red Dot sight
    S&J Hardware Non-binding nylon follower
    Nordic Components Magazine Tube Clamp & Rail
    Nordic Components Magazine Tube Extension
    Gun Connection NOB Gen 2

    Trijicon 4MOA MRD:
    I actually got the MRD to use on another project, but due to my dislike of the fiber optic sight shortcomings I decided to try it out on the SPX. My intention was to use the illuminated red LED to speed up targeting and offset the need for light on the front sight. When I started to look at various red dot sights, the Trijicon offering had several features that made it stand out from other similar units of the rather crowded MRD market; I mainly liked the light weight of the sight and the waterproof LED. Another benefit was the adjustment of the sight’s windage and elevation: there were no set screws to tinker with. That the sight was backed up by a giant in the industry with a good reputation for customer service was another plus.

    View from the front of the MRD, showing the LED emitter.

    The Trijicon MRD 4 MOA sight is a miniaturized red dot sight. The sight was intended by Trijicon to be a backup unit for ACOG scopes to provide the shooter with an enhanced CQB capability. It consists of a glass reinforced nylon body and hard-coated acrylic window upon which a waterproofed LED projects a small (4 MOA) dot. A photosensor adjusts the brightness of the LED to ambient light levels. Using the standard battery, the dot is rated to have a life of 2 to 3 years depending on the brightness. There are no external switches to switch the sight on or off or to adjust the brightness. The opaque hood included with the sight is used to not only provide protection for the sight when not in use, but it also functions as a means to put the sight in its lowest setting, prolonging battery life.

    Top view of MRD, showing mounting screws and elevation adjustment.

    Like with other optics of this sort, I preferred to be able to mount the sight so that I could cowitness the irons with the dot. If this wasn’t possible I at least wanted to be able see the irons through the sight window.

    As per the manual, I installed the 3V 2032 battery in the base of the Trijicon sight and screwed it to the Picatinny rail base by indexing the four locating studs on the bottom of the sight into the corresponding holes in the base. A mount with protective wings (similar to those on the LPA irons) is available, and the only reason I didn’t chose that version was that I was worried that it would put the sight too high to be able to cowitness with the irons. I would have liked to have the added protection of the wings, but with just the Picatinny base the sight was already sitting fairly high.

    Side view showing Picatinny mount and the tension set screw.

    After the sight was secured to the mount, I mounted it in front of the LPA sight on the SPX’s rail. Looking through the ghost ring aperture, the dot appeared rather high, and I needed to bring the dot down to get it inside the sight axis. A reference dial and hex wrench are included with the sight to make adjustments. The dial has a small hole in the center through which the hex wrench is passed. The outer rim of the dial is marked with hacks that show ¼” shifts at 20 yards. The adjustments on the sight are made by inserting the hex wrench with the reference dial into the windage and elevation sockets at the rear of the sight. The elevation is set using the socket in the top rear of the sight, and the windage is set using the socket on the right rear. Trijicon lists the sight as having 25 inches of adjustment in both axes at 20 yards, which is completed in one full turn of the screws. There is a hex screw at the left rear of the sight, but this is used to set the screw resistance at the factory and should not be turned by the user.

    I brought the dot down into the ghost ring so that the sight would be fairly close based on the zero of my iron sights. At this point, it appeared that I was going to able to cowitness the sight with the irons, so I set out to confirm this. I had used up a lot of the drop range, so I hoped that there would be enough left if I needed to bottom it out more. After a few rounds, I noticed drift in the sight. I checked the tightness in the rail mount screw, and it seemed good to go. However, the sight base screws could stand a little tightening. I was worried about over tightening them and damaging the threads or sight body as there was no torque setting given in the manual. So I went ahead and tightened it down more. Unfortunately the dot had risen back above the sight axis and I was out of adjustment. I went ahead and fired of some more rounds, and the dot had ceased moving, so I had solved that problem at least.

    At this point I was able to zero the sight by changing my cheek weld. I now had two different sights on different planes and I could not use the irons with the MRD installed. Not acceptable to my desired end-state of a cowitnessed dot and irons, which I wanted in the event that the MRD failed. I didn’t want to have to remove the sight in order to use my irons, which was the case as things were. I put the cowitness issue on the backburner at this point and started working out the sight.

    The dot was suitably bright in almost all lighting conditions. In daylight the dot was easy to pick up and visible against all backgrounds. The 4 MOA dot size allowed for quick enough acquisition while not covering too much of the target. Unlike some other automatically adjusting sights that will “strobe” when in a very dark environment the Trijicon does not do so. Even in a totally closed off room with no ambient light the LED dot is still steady. The only problem that I encountered was in part due to the automatic photosensor adjustment. In dark environments the LED is at a very low setting and can be hard to see against a light colored background when a weapon light is used. The dot can be found with some effort, but that takes time which may not be available.

    In order to compensate for the sight’s inability to manually set the brightest setting I decided to increase the battery power. The user manual indicates that in unusually bright conditions the MRD battery can be replaced with two CR 2016 batteries. That provides the sight with 6V of power to increase the brightness of the LED. This comes at the corresponding cost of halving the battery life. Since this would theoretically be 1.5 to 2 years, I can still live with that. It would simply be a matter of making battery replacement a part of annual inspection in order to make sure the batteries were always in good order. After stacking the batteries, the weapon light problem was almost completely solved. Against a white background, the dot can still be hard to pick up. It does not appear that there is any way to correct that.

    View showing arrangement of LPA rear sight and MRD that allows a cowitness.

    After fixing the dot brightness issue, I decided to revisit the cowitness problem. Trijicon offers shim kits for the sight to “add in” sight adjustments much like sloped scope base for long range shooting. However, because I needed to keep the sight as low as possible, I decided to try the old school method of shimming the sight with a thin layer of metal at the base. After remounting the sight with the shim to the Pic rail, the dot was closer, but still not in the cowitness neighborhood. Looking at the geometry of the sight axis, I decided to rearrange the sight and the LPA irons on the rail. By moving the LPA forward the sight axis angled upwards at the rear as well. I then placed the MRD at the rear of the rail, which now had more room in adjustment to cowitness to the same axis as the LPA irons. I brought the dot into rough alignment with the ghost ring and tested it. Finally the MRD was cowitnessed to the LPAs. With this arrangement, the dot against the front sight post actually appears very much like the fiber optic sight. In a way, this also helps with the white target/weapon light contrast issue. With the dot cowitnessed to the front sight blade, the dot can be seen against the silhouette of the front sight blade, and the front sight blade should be quite visible when using a weapon light.

    Cowitness sight picture. The 4MOA dot gives much the same image to the shooter as the FO tube.

    At this point I continued to test the sight, and it has done well. When sighting in the MRD, I recommend using a range of not more than 20 yards. This is due to several factors. First, the sight does not have positive click adjustments. Adjustments are as fine as your own dexterity in turning the dial and hex wrench arrangement. At longer ranges even the slightest turn is going to shift the POI significantly. Second, the dot is fairly large. In using the 4 MOA unit I was trying to not conceal as much of the target as would be the case with the 8 MOA. Even then, at ranges over 100 yards the dot is getting fairly large, and at 50 yards it is fairly good sized. Because this is intended as a backup CQB unit, that is fine and fulfills its role.

    For its intended purpose, the Trijicon MRD is a good choice. It is an excellent up-close sight for the shotgun, and is very economical as well.

    Technical Details:
    Magnification: 1x
    Sight Window: 21.6mm x 15.4mm
    Elevation adjustment: 125” at 100 yards
    Windage adjustment: 162” at 100 yards
    Recoil resistance: 5,000g
    Operating Temp Range: -13F to 131F
    Storage Temp Range: -40F to 158F
    Power Supply: 1xCR2032 (3V)
    Dimensions: 42mm x 25.4mm x 23mm
    Weight: .5oz
    Light Transmission: 98%
    Included with sight: Snap on cover, adjustment indicator dial, adjustment hew tool, hardcase, manual, battery

    S&J Hardware Non-binding Nylon Follower:

    Rear view of follower showing clearance cut and tail. The material is self-lubricating.

    Simon Beeson of S&J Hardware produces a range of shotgun accessories. These include full length top rails, a variety of bayonet mounts, shotgun magazine extensions, and other precision machining operations. His shop is located in Canada, but there are several distributors carrying his products in the US.

    The S&J follower installed. The nub allows the user to verify loaded/unloaded status without looking.

    For my SPX I selected a hi-vis shotgun magazine follower from Simon. I wanted the added capabilites of an aftermarket follower over the stock unit. This unit is machined of bright orange nylon in order to provide a highly visible cue for visual magazine checks. The front of the follower has a prominent nub that can be felt to provide tactile verification of an empty magazine in low light situations or if the shooter needs to keep his eyes up. At the rear of the follower there is a spring guide that prevents the spring from doubling over under compression.

    Front view of the S&J follower showing the tactile nub. Combined with the hi-vis color the follower allows rapid verification of mag status by feel and sight.

    While this follower sounds similar to many others currently on the market, there is one design feature that sets this one apart from the rest. The S&J follower has two clearance slots machined in the sides. If you are using an 870 Express or similar shotgun with dimples in the magazine tube, you have been forced to either keep the factory follower in the tube or drill/press out the dimples in order to use an aftermarket follower. With the S&J unit, owners of dimpled magazine tubes may now use a hi-vis non-binding follower without having to physically modify their shotgun. The slots allow clearance for the dimples while the follower is slid into the magazine tube. While these followers are desigend for the 870 Express, S&J manufactures these to fit a variety of shotguns including the Mossberg 930 SPX.

    The material of the follower allows it to slide through the magazine tube with little friction. While not needed on the SPX, the clearance cuts in the side had no detrimental effects. The follower has operated as intended, and is better suited for a defensive gun than the factory follower. While I have been pleased with the performance of the follower, it does come with a price. Like all nylon followers that have the spring guide tail, it may cause the shotgun to lose one round of capacity.

    Additionally, the follower is not meant to be used in dimpled shotgun magazines with an extension attached. The follower does not have any means of maintaining proper alignment and should only be used in dimpled mag tubes that do not have an extension. If the user wants to use an extension, the dimples will still need to be removed in some way.

    Nordic Components Magazine Tube Clamp and Rail:

    Left side of clamp, which was left clear of the optional sling button and rail.

    I often get asked about magazine tube clamps and if they are needed. For some maybe not. But if you expect to ever have your shotgun in a situation in which it might get bumped, they provide support for the magazine tube to keep it from getting bent. With some shotguns, this can result in a trip to an armorer or factory repair center. Another benefit of the clamp is to provide a means of securing the magazine tube extension and keep it from backing out under use. A third benefit of the magazine tube clamp is that it can provide a place to position a rail forward on the shotgun. This rail can be used for lights, lasers, or a sling point just as any other Picatinny rail.

    Because I want a light on my SPX, I need a forward rail. Over the time that I’ve owned the shotgun, I’ve tried three or four different clamp and/or rail arrangements. None of these have been completely satisfactory, and some have been outright disappointing. Nordic Components has a tremendous reputation among competition shooters, and their extensions and clamps are rated among some of the best. I contacted Chris Patty of Chris Patty’s Winning Shooting Accessories LLC and asked him a few questions about the clamp. Chris was very helpful and offered great customer service. After talking to Chris I ordered the Nordic clamp with rail section.

    The two halves of the clamp with their screws. Also shown is the optional Nordic Components rail section.

    The Nordic clamp consists of two butterfly-shaped halves that screw together using two hex head screws, one from either side. Nordic did a superior job in manufacturing the clamp. The machining is clean and there are no tool marks or burrs. The finish is clear black matte with no scratches or spots. The two halves fit perfectly without any gap or misalignment. The larger diameter section goes around the magazine tube. The clamp has a relatively large footprint to secure and grip the tube and barrel, without being overly large. The two clamping screws go in the holes fore and aft on the clamp. During installation the clamp halves fit together easily, and the screws were easy to start. Once the screws were started but not quite tightened, I made sure that the clamp was correctly positioned and tightened it down. A thread locking compound can be used if the user is sure that the clamp will not need to be removed for maintenance or other reasons.

    Shooter's view of the rail installed on the clamp showing compactness of the system.

    A third threaded hole is in centered on the clamp on each side. This hole is meant to be used for either attaching the optional Nordic Components Picatinny Rail section or to attach a threaded sling button. It can also be left empty of course. In this way, the user may add whatever combination of sling button (one per side) or rail (again one per side) they want or leave both sides clean. Because I wanted the rail to mount a light, I installed the Nordic rail section. This was another benefit of the Nordic Components clamp that makes it stand out over other offerings. The Nordic rail is not only relatively short, it does not protrude prominently to the sides. They are fairly close to the barrel axis.

    Clamp with optional rail installed. The rail section does not extend past the forward and rear edges of the clamp.

    The rail section fits securely against the shoulder of the swell for the magazine tube ears. Once secured it fits tightly and provides ample room for lights or whatever the user desires to mount with 3 cross-slots. I used the rail to mount my TLR 1. I left the other side open, as I don’t need another rail for a laser, and I’m still using my SGT side sling mount. With the clamp and rail positioned well forward, I was able to place the light where there is no shadow from the muzzle.

    Chris Patty:

    Nordic Components Magazine Tube Extension:

    When I ordered the mag tube clamp from Chris Patty, I had wanted to get an extension as well. While the stock extension tube was alright, there were some aspects that I thought could have been done better. The finish has worn on my original, and the plastic end cap has gotten out of position when poked once or twice. Chris was out of the extensions at the time, but he emailed me a few weeks later to let me know he had gotten them in (more of that customer service I mentioned). I ordered the +2 extension from Chris and waited for it to arrive.

    Nordic Components +2 magazine tube extension with standard cap.

    Some people may ask what makes one extension different from another, or think that they are all pretty much the same. While that is true for some extensions, I quickly learned what separates the Nordic Components extension from others. While the cost is significantly higher than other extensions the price is clearly reflected in the quality that goes into the extension. Not only in the material and manufacturing of the product, but also in the innovative features of the extension.

    The package includes the 6” extension body, instructions, and an untrimmed 40” spring.

    Like the clamp, the extension has a flat black finish that closely matches the Parkerizing on the SPX. The weight of the extension assembly is surprisingly light. The extension nut has widely spaced knurled channels for almost the full length of the nut. The cuts are relatively wide and deep and are angled to provide a good gripping surface.

    Large, shallow grooves on the extension nut provide positive gripping surface for hand-tightening. The rear edge of the nut is scalloped for a detent.

    The unique characteristics of the extension become evident on reading the instructions. The extension body actually consists of three parts: the extension nut, the body tube, and the cap.

    The extension cap, tube body, and nut. Note the hole in the cap for the insertion of a cleaning rod.

    This allows several possibilities that will be discussed later. The threading for the various parts is finely cut and is of very good quality. The threaded sections of the tube are long and provide for plenty of area for the cap and nut to grip the body.

    When installing the extension, the cap is removed from the body and the extension nut and tube are screwed onto the magazine tube of the shotgun. The instructions indicate that the nut can be hand tightened in the event that the shooter needs to remove the extension without tools in the field. I then placed the S&J follower in the magazine tube and began to prepare the spring.

    The spring is a high quality unit that has to be trimmed to length. The instruction sheet directs the user to trim the spring to about 10-16” longer than the mag tube and extension body. By letting the user determine the spring length, a more or less positive feed can be had. For less power the spring is trimmed shorter while for more power the spring is left longer. I trimmed mine slightly long so that the last rounds in the mag tube are fed more forcefully. I measured out 16” of additional spring length and added a little bit more to that measurement. I then cut the spring and reshaped both ends so that it would nest flatly against the inside of the extension cap and the follower. After the spring is placed inside the magazine and extension body the cap is fitted. In order to facilitate this, Nordic provides a hole in the cap through which a cleaning rod can be passed. This rod is extended down into the magazine against the follower and provides a guide upon which the spring can be compressed under the cap without doubling over on itself. The cap is screwed down onto the threads of the body tube until it is snug.

    The extension cap partially threaded onto the extension body.

    Once installed, the extension is solid and doesn’t shift. The total length of 6” takes the end of the extension to just short of the muzzle. With the S&J follower and the extra spring length, the magazine capacity is now 6 rounds, down from the factory 7. However, this is where some of the innovations built into the extension by Nordic Components come into play. Nordic offers an extended end cap that adds about ¾” to the extension, which is enough room for the 7th round to be inserted in the magazine. Furthermore, the threaded body can be replaced by one of another length. In that way, the capacity can be increased by as many rounds as desired by using longer tubes available from Nordic. These tubes can be screwed into the extension nut already on the shotgun. This will allow different magazine capacities without having to buy entire extensions. I’m looking forward to adding an extended cap to my shotgun to regain the full 7 rounds of capacity.

    Nordic also offers an extended cap that gives the user an extra 3/4" if just a little more room is needed in the mag tube. For those with the longer magazine followers, it gives a little more room and may allow you to regain the shell that is generally lost when using one. It may also allow you to regain full capacity when loading slugs or other rounds that are slightly longer than the average shotgun shell.

    The Nordic extended magazine tube cap brings the length almost all the way out to the muzzle.

    One of the interesting features of the removable end cap is that the cap and mag tube spring can be removed from the extension to practice loading. With the cap off, the loaded rounds will fall clear of the extension, and the user can keep working on the reloading mechanics as long as desired without having to download.

    It is also possible to remove the cap and have full access to the magazine extension. This allows the user to perform PMCS that would otherwise require the removal of the magazine extension for users of other systems. If there is a magazine clamp assembly, that has to be removed as well. With the Nordic system, that is no longer needed. This simplifies the procedure considerably.

    I have been very impressed with the high standard of Nordic Components’ accessories. For me, the price of the extension is well justified in its quality and execution. The small details of construction and capability make this the finest extension I’ve ever bought, and I have had many. No other extension parallels the offerings of this equipment.

    UPDATE 26 July 09:
    For whatever reason, Nordic has changed the nut on their Mossberg extensions. In doing so, the current extensions will not work on the 930 mag tube. Nordic is aware of the problem and is working on a new nut that will work with the 930. If you are set on buying a Nordic extension I would either make sure that you have old stock that will work or wait it out until Nordic goes back to making a nut that will work with the 930 again.

    Gun Connection's The NOB enlarged bolt handle:

    The NOB shown installed on the SPX. The micro-grooved surface is just visible along the outer edge of the head.

    I’ve been using The NOB from Craig at Gun Connection for quite a while. He has recently produced the second generation of NOB that improved an already very good product.

    The stock bolt handle is the same unit found on the hunting 930s, and stays true to the sporting nature of the original. It is fairly small and pointed on the end. While that is fine for the sporting use it was originally intended for, it leaves a lot to be desired on a defensive gun, or one that is to be used in competition. Rain, mud, blood, sweat or other fluids can make the surface of the bolt handle hard to grasp. The small size doesn’t help in this regard. When operating the bolt while trying to retain a firing grip on the shotgun, the small size of the bolt makes it a small target for the support hand that is reaching either under or over the receiver to operate the bolt without looking. Additionally, the pointed shape of the factory handle can stab a left-handed shooter.

    The first generation NOB next to the factory 930 bolt handle.

    The NOB started out as an effort to improve these shortcomings. The first generation NOB was a significantly longer and thicker bolt handle with a large flat head on the end. It was manufactured of steel and had a ceramic heat-cured finish. The lengthened handle and enlarged head allowed for easier manipulation of the bolt. The flattened head also prevented the stabbing experienced by lefties. I was fortunate enough to have been one of the testers for the first generation NOB, and was completely pleased with it. It enhanced the capabilities of the shotgun and allowed the user to manipulate the bolt much more easily. I used and abused the NOB and it took everything without any problems. The fit was secure, and function was flawless.

    Side by side view of the first generation (bottom) and second generation (top) NOB. The grooves are more evident in this view.

    Craig continued the evolution of the NOB and improved it with a few enhancements. The finish was changed slightly with a more granular coating. The head was increased in size to provide more positive handling. Finally, the NOB was given a microgroove finish similar to AK barrels. This also improved the grip of the handle. Due to the finish wear of the first generation NOB the engagement services of the NOB were left unfinished.

    Close up view of the NOB. Second gen is on the left.

    Unlike some other enlarged bolt handles the NOB will allow for an EOTech to be mounted on the SPX without clearance issues. The NOB will move freely and stay clear of any optics mounted on the rail. Some enlarged bolt handles also have a very large spool-type structure. While that will help to make the handle more easy to engage, I don’t care for the extremely large size. The size of the NOB is ideally compromised between the two extremes of unwieldiness and ineffectiveness. The NOB fits well enough that I am able to pick up the shotgun by the NOB alone. The finish has held up well through use, although I have not tortured it to the extent that I did the first generation model. The large target created by the NOB facilitates manipulating the bolt. The head of the NOB helps to keep the hand from slipping free of the bolt handle when sweeping the bolt to the rear from underneath the receiver. The microgrooves have helped to add to the easy grip of the NOB.

    Craig can be reached at:

    Another view of the NOB.

    In addition to the 930 series, the NOB will also fit on the old Mossberg Jungle Guns.
    Last edited by m24shooter; 21 March 2009 at 10:29.

  6. #6
    Join Date
    Aug 2007
    A few more items to add to the review:
    Ghost loading
    Sidesaddle modification

    Ghost Loading:
    It is possible to ghost load the 930 SPX. This allows an additional round to be placed on the carrier. If your shotgun has a follower with a tail like the Vang, SGT/Wilson or S&J models, you lose a round of capacity. Some shell lengths will also cause you to lose a round of capacity even with a standard follower.
    Ghost loading lets you bring the capacity back up to the listed capacity or gives you an additional round if you want it. Another use for ghost loading is carrying the SPX in a vehicle. With ghost loading you can keep the full 8 rounds with the initial round on the lifter and not worry about the problems associated with a chambered round in a weapon with no firing pin safety.
    I've found two methods to ghost load.

    Procedure 1:
    -Load the mag tube to capacity (6 or 7 rounds).
    -Slide bolt to the rear, stopping right before the shell release is tripped.
    -Push one shell through the ejection port and below the bolt, resting on the lifter. You might have to push the lifter down slightly. Push the shell rearwards so that the base is under the leading edge of the bolt.
    -Place another shell in front of the bolt, and allow the bolt to close and chamber this round. This step can be eliminated if you don't want a round in the chamber. Just make sure the bolt face passes over the round positioned on the lifter and does not pick it up.
    -You now have one chambered (unless you decided to omit this step), one on the lifter, and a full mag tube (6 or 7 rounds, depending).
    This will take some practice to get used to where the mag tube releases the ready round, and actually being able to hold the bolt back while ghost loading one round and chambering the other.

    Procedure 2:
    There is a quicker way if you can't get the 7th round fully in the mag tube, but only lack about 1/4" approximately to fully load the final round.
    -Chamber a round. You can also omit this step if you don't want a chambered round but still have 7 or 8 total rounds.
    -Load the mag tube to 6 rounds.
    -Take the 7th round and push it as far into the mag tube as you can. Push it in far enough to clear the forward edge of the lifter.
    -Once it is clear of the leading edge (so the lifter can come back down) let go of the pressure on the base of the 7th round. You might want to "roll" your thumb back slightly, so the round is guided on top of the lifter. This round will shoot backwards, now inside the receiver and on top of the lifter if you get it right.

    Sidesaddle modification:

    The TacStar 870 Sidesaddle modified to fit the 930.

    Up to this point, nobody has come up with a sidesaddle for the 930 series. The velcro/adhesive type can work, and Mesa has been working on one for several months. TacStar has said they don't plan on making one. This leaves either more waiting or modifying an existing version to work with the 930. I've been on the verge or modifying one for a while, but Vellcrow at Arfcom went out and did it. Full credit goes to him for coming up with the actual materials and procedures, which are as follows:

    If someone wants to do this, you need the following:
    - 10-32 tap
    - #21 drill bit
    - two 10-32X1.75" button head socket cap screws
    - four plastic washers (don't remember the technical name, but they were item # 3817H at ACE)
    For mine, I changed this slightly. I used the following:
    -TacStar 870 sidesaddle (either the 4 or 6 round)
    -10-32 NF tap
    -#21 drill bit
    -two 10-32 x 1.75" Phillips button head machine screws
    -two steel washers

    I went with the 4 round sidesaddle because while I want to carry extra rounds on the shotgun, I don't want to add a lot of weight to a greatly-balanced shotgun.
    I also departed from Vellcrow's socketed screws because I have a Phillips driver on my Gerber tool.

    The sidesaddle does not interfere with the manipulation of the safety. The rear sight base screw does not prevent extraction of shells.

    -Remove the two trigger group pins, and then the trigger group.
    -Remove the plastic shell holder from the aluminum frame.
    -With the 870 sidesaddle, you already have one 10-32 hole. Use one of the machine screws to position the frame on the side of the receiver using the forward trigger group pin hole. Using a center punch or scribe, mark the location of the rear trigger group pin hole. Remove the machine screw and frame from the receiver.
    -Drill the second (rear) hole using the punch/scribe mark that you made.
    -Tap the hole.
    -Return the trigger group to the receiver and push the machine screws through the holes to hold the group in place.
    -Screw the plastic shell holder back onto the frame. Use threadlocker on the small screws to make sure they don't back out under firing.
    -Screw the sidesaddle assembly onto the receiver. Do not overtighten the screws, which may pinch the receiver and bind the action. You may want to use thread locker on this, which is what I did.

  7. #7
    Join Date
    Aug 2007
    I got a call from Mark Kresser (VP Sales & Marketing) with O.F. Mossberg today in response to a letter I wrote. The letter focused on issues that were rather widely known to 930 SPX users but that were seemingly ignored by Mossberg customer service, and the poor response provided by customer service.
    So today Mr Kresser called. I was surprised to say the least.
    He started off with sincere apologies about not only the problems encountered by 930 SPX users, but also for the problems with the service department and the lack of or poor response. We talked about that for a while, and Mr Kresser was very sincere in this, and I believe that he meant what he said.
    He indicated that there were changes being made, and that they were trying to work to correct the issues.
    As lots of people have suggested, a large part of the problem is the huge wave of gun purchases made leading up to and following the national elections. The factory has been trying to keep up with production and vastly increased demand with basically the same manpower that they had before.
    The particular issue of the canted sights and POI issues was explained as being a result of two issues. The canted sight is a result of jig and fixture problems. Some of the barrels were not put in the fixtures correctly, which resulted in the sight being canted. The POI shift is due to the sight height of the rail mounted rear sight in relation to the front.
    I asked if new production shotguns were leaving the factory with the new sight arrangement, and he said that they were.
    Another issue that possibly contributes to the POI shift is barrel security. Depending on how much torque is exerted upon the barrel lug by the mag tube cap or extension, there will be variations of tension upon the barrel. While we didn't specifically talk about this, I would expect that there may be some harmonic issues as well and certainly consistency/repeatability based on slop between the barrel lug, mag tube cap, and receiver.
    Another topic was the service response. Mr Kresser reported that some of the problem is being able to find staff with the skill and knowledge to do repairs/service. Like any other skilled job, it can be difficult to find somebody who isn't already working somewhere else doing the job you need done. In addition, there isn't just a huge market or demand for gunsmith work as there has been in the past so the feeder stream is rather small. And if you've never been to Eagle Pass, I can tell you that it is not exactly an industrial megacomplex and I can see why it would be difficult to find the desired labor pool in the immediate area.
    Mr Kresser also invited me to the Mossberg factory in Connecticut. I've been asked to come in and meet the engineers and tour the facility. Mr Kresser asked me to provide input on potential improvements, corrections for problems, and suggestions on how to make the platform better. He also related some things that they are working on now and said they had some interesting things to show me. I can't get into all of that now, but I think down the road I will be able to. Mr Kresser advised that they wanted to hear my ideas, we could talk about it, and if it was something that couldn't be done they would say why. I'm very excited about the possibilities here, and eagerly looking forward to this opportunity.
    I've never had a VP call me in response to a letter about their product. So it was not only surprising but humbling to know that a corporate officer was taking the time out of what I'm sure is a hectic day to respond in person to my concerns and extend a personal invitation to meet with Mossberg staff. As I said, I was impressed. I got the impression that Mr Kresser was genuine in both his concern and apology and in Mossberg's desire to make things right for the customer.
    Mr Kresser asked that I pass this info along, and I think that is more than a reasonable request. I had planned on it anyway, but Mr Kresser wanted to make sure that we know changes are being made even now at OFM.
    I will be sure to follow this up as the situation plays out, and I'm hoping that work and family schedules will let me do this in the next month or two.
    In the meantime, I will be collecting everything I can think of to talk to the Mossberg staff about.

  8. #8
    Join Date
    Aug 2007
    This post will begin my next series of updates to this 930 SPX review. These will cover the Aimpro Tri-Rail, the Nordic Bolt Handle, and also some Elite Tactical Advantage items. I hope to have all of these posted in the next day or two, and another update in the very near future. I will also be posting some information that some readers have sent me or that they have posted on various boards. Finally, I want to put some information up on the problems that are either still being seen or as in the case of a few issues some new ones that have popped up.
    I would like to thank everybody who has been following this update over the years, and especially those that took to the time to converse with me about it. I'll keep updating it.

    The new Aimpro Tri-Rail
    Users of the Mossberg 930 SPX have long wanted a means of mounting lights, lasers, fore grips of different types, and slings. The factory forearm and complete lack of front sling mounting point left those users high and dry. Lots of stop-gap, improvised measures were used to come up with a usable solution.

    Mike Shain at Aimpro decided to fill this need with the Tri-Rail. Mike Shain is a former LEO that got into shotgun work in the 90s. He operates Aimpro in Colorado as the Mossberg Law Enforcement repair center. In addition to repair work Aimpro offers training for law enforcement, the military, and the private citizen. On top of all this there is a healthy research and development operation that produces a wide variety of custom shotguns, accessories and modifications to the Mossberg line. The latest addition to the Aimpro shotgun line is the Tri-Rail.

    The rail is constructed of 6160 T6 alloy with a black anodized finish. Aimpro used Type II anodizing for the surface finish. Mike explained that they tried Type III but that they felt that the additional hardness was of minimal improvement and just added unnecessary cost. The bottom and both sides of the forearm are covered with full length mil-spec Picatinny rails. The side rails are of the plow-type, meaning the center of the rail slots is not present. The bottom rail is a standard rail with the rail lugs spanning the full width. The slots are not indexed with “L/B/R” numbers.

    Since receiving the Tri-Rail I’ve been asked several times about differences in weight and size between the factory forearm and the Tri-Rail. The rail measures 11.15” in length, 2.2” in height, and is 2.25” wide. It weighs 17 ounces. The factory OEM forearm is slightly longer, 1.88” wide, and 2.17” tall. It weighs a little over 6 ounces. The Aimpro Tri-Rail is a simple drop-in replacement for the factory forearm, and no fitting or gunsmithing is needed to install it. If you can break your 930 SPX down for basic cleaning, you can install the Tri-Rail.

    Top view showing relative widths of the two units.

    Side view.

    The actual differences are remarkably small. Very little width and height are added to the forearm dimensions. While there is obviously a significant increase in weight relative to the factory forearm, the weight increase is less than ¾ of a pound and with the location of the forearm the weight is added in such a way that it is not detrimental. The balance remains largely the same.

    The rail arrived in a sealed plastic sleeve, wrapped in shipping foam in a heavy cardboard box.

    The package includes the rail assembly and 12 soft rail ladder covers.

    Currently, only the black finish is available for the rail. Mike said that they intend on eventually adding other colors such as the OD and tan finish for the rails. The ladders cover the rail with 4 needed per side for full coverage. Again, black is the typical color unless the buyer specifies the OD or tan versions. Aimpro can include these colors but it will take an extra day or two to complete the order as that will be handled as a custom order.

    Bottom view of the rail assembly. End closest to camera is the receiver end.

    Muzzle end view of the rail. This view shows the collar that fits the rail to the barrel lug/piston collar.

    Side view of muzzle end of the rail assembly. Screws secure the collar inside the rail body.

    Normally, the factory forearm spaces the magazine tube extension nut from the barrel collar and is held in place between the two. The Tri-Rail uses a similar arrangement, with the plug serving this purpose. The screws visible in the side of the rail body are the connectors that hold the rail body to the plug. The screws remain in the rail body assembly and are not meant to be adjusted or removed.

    Looking inside the rail body, from the receiver end towards the muzzle end.

    Just visible on the plug at the muzzle end of the rail you can see some small cutouts on the inside surface. These are gas bleed off chambers that were specifically cut to provide space for the bleed gasses to expand as they are vented from the barrel collar. These gasses typically escape from around the collar and into the area underneath the forearm. Mike explained to me that they did a gas flow study to determine the optimal pattern for the gas that is vented from the shotgun. According to Mike, these expansion chambers also help to make the shotgun run more reliably with low powered rounds. The new compression ratio created with these cutouts is supposed to make this possible. So in addition to the benefit of the rail surfaces some users may see a reliability improvement as well.

    Receiver end of the rail body.

    930 prepared for installation of the rail assembly.

    Rail installed on the 930 prior to the mounting of the extension nut.

    As I said, if you can break the shotgun down by removing the magazine extension and barrel for cleaning, you can install the Tri-Rail. Simply remove the magazine tube extension by unscrewing it (you can also use the rail on the other models of 930 that don’t utilize the mag tube extension), and then remove the factory forearm. Swap out the Tri-Rail and guide the assembly over the mag tube and gas assembly. Make sure the rail assembly is firmly seated against the barrel collar and pushed back so that the rear overlaps the receiver and then re-install the mag tube extension or mag tube cap and tighten it down as normal. With that, the rail is installed and ready for use.

    Extension and TLR installed.

    One of the issues that I had with the factory forearm was the overhang of the rear of the forearm body over the receiver. The tail of the forearm extended back very close to the loading port, and protruded downwards significantly. This for some was not a problem, but if you index with the front of the loading port and receiver while loading your shotgun as I do, it could get a little crowded. I decided to cut the tail off of my forearm to allow for a little more room for my support hand index finger knuckle to rest against when pushing the round in past the shell latches. The SPX has been known to cause problems for some when loading because the shell does not get pushed past the latches. When this happens and the thumb is withdrawn from the loading port the round squirts back out of the magazine tube and ends up resting on top of the lifter. While the shotgun can be fired in this configuration, if you want to keep loading the magazine this situation can be problematic. Cutting the forearm tail clear of the loading port to me at least makes pushing the rounds fully past the shell latches much easier and minimizes one possible area of operator-induced malfunction. In light of this, I was very happy to see that Mike had designed the rail to be just about the same length as the modified OEM forearm that I had cut down. The bottom of the rail surface also doesn’t protrude such that it makes loading difficult. This shows some of the careful thought that went into designing and building the Tri-Rail.

    OEM unit.

    OEM with m24 modification.

    Aimpro rail.

    The Tri-Rail as mentioned solves one of the truly baffling oversights that O.F.Mossberg left on the 930 SPX: a complete lack of a forward sling attachment point. For some unknown reason, the factory version cannot accept a sling with only the built-in sling point on the buttstock. Now, how you sling up a shotgun that only has one sling point almost at the toe of the buttstock I don’t know. But this omission left users having to use sling plates intended for other shotguns, magazine tube clamps with sling points built in, or rail adapters with sling mounts for the forward sling attachment. With the Tri-Rail, the user now has the option of using a variety of sling mounts that are intended for use with rail systems. I’ve used several sling points on the front including Gear Sector, MI, and Daniel Defense of various types.

    I’ve also been asked about if that much rail is needed on the shotgun, or any rail at all. The answer is: that depends. Obviously, not everybody uses a shotgun for the same reason. For the purely look/cosmetic oriented user the Tri-Rail provides a means to add whatever they want to the shotgun. Lights, lasers, grips, anything and everything can be attached so long as it has a means of attaching to a Picatinny rail.

    For the more practical oriented user the rail provides lots of options. The practical user may not need all of the rail surfaces, but they may want to move a smaller number of items around to various places on the shotgun based on their immediate need. Obviously without index marks, that will be more difficult than if there were etched markings for reference. However, the rail does allow the shotgunner the chance to mount the following all at the same time: a sling, light, and foregrip or handstop. All of these things are well within the realm of items in standard use already. The popularity of the Magpul Dynamic methodology of thumb-over-bore shooting style has crossed over from the carbine to the shotgun, and there were already a lot of users that wanted a VFG or AFG. A light is essential in a defensive or duty role, and a sling is another well-advised addition to a long gun. With the Tri-Rail you can put all of these things on the shotgun without cramming them onto a factory forearm with field-expedient modifications.

    Close-in view of rail with TLR.

    Top view.

    Right side.

    Left side.

    An interesting use of the rail is for 3 gunners that want to mount an offset MRDS-type sight. The rail provides a place to mount something like a Daniel Defense 1 o’clock rail mount for something like an MRDS, RMR, SPARC, or Micro. I decided to try this out and see how well it would work. Just like the MRDS that I use on my SDM build I was able to mount the MRDS on the side rail. This would allow the 3 gunner to use their iron sights for close in buck and hold off for slugs in close, and then have the optic zeroed for longer ranges for slug targets.

    Now users of the SPX have a full-length railed forearm replacement that provides a place and means to mount virtually any accessory desired. I’ve really enjoyed working with the Tri-Rail and it has finally provided a well-thought-out and high quality aftermarket forearm replacement that offers a stable and durable means to mount a light, sling point, and hand stop to my shotgun without worrying about screws pulling out of the thin factory forearm.

    The Tri-Rail is listing with Aimpro for $149 including the ladder rail covers plus shipping.
    The number to call for ordering is 303-838-0200.
    Aimpro has them on their website now.

  9. #9
    Join Date
    Aug 2007
    Elite Tactical Advantage Enlarged bolt handle and safety

    Elite Tactical Advantage is a new operation specializing in shotgun accessories. Mark Mueller has brought some pretty interesting items to market for both Remington and Mossberg shotguns. His outfit has developed several different rails for pump and semiautomatic shotguns. Among his offerings are an enlarged safety for any of the Mossberg shotguns and an enhanced bolt knob for the 930 series.

    ETA Enlarged Bolt Handle

    The ETA bolt handle is a knurled solid-cored design. It is slightly shorter than the NOB, and slightly longer than the Nordic version. It has a matte black finish and the knurling goes all the way around the outside of the knob. A shallow scooped front edge is left smooth on the front surface of the bolt knob. Mark said that he wanted to develop a bolt handle that didn’t have a doorknob on the end of it, and if that is something that sounds like just what you want the ETA model may be the bolt knob for you.

    Left to right: The NOB, ETA handle, Nordic handle.

    The ETA bolt handle installs just like the OEM model. You remove the OEM handle by simply pulling it straight out of the bolt body, and then push the ETA model straight in. The handle locks securely into the bolt against the detent and is held securely.

    The bolt handle installed.

    The ETA bolt handle allows for operating the bolt from the weak side by reaching over the top or from underneath with the support hand. It is large and long enough that it can be easily located without having to look for it. The scallop on the front surface helps the finger or thumb get a better hold on the handle.

    ETA Enlarged Safety

    The next ETA item I looked at was the enlarged safety for the 500/590/930 and similar shotguns. There are several safeties available for the Mossberg shotguns and ETA decided to take a slightly different approach. Several of the safeties are taller, and one is slightly wider. The Cav Arms unit is very wide, and meant to be used with their rail adapter stocks.

    The ETA safety is an arrowhead shape design and machined from aluminum. It is quite a bit wider than the factory and Vang units, and is slightly taller. With the ETA safety the user can install it “pointing” either up or down. My personal preference was to install it pointing up. The slightly taller ridge of the ETA safety very closely followed the contour of my thumb when it was resting on top of the safety. This was a very natural position and when I picked up the shotgun my thumb just naturally felt out the safety.

    The enlarged safety and associated parts.

    Compro between the ETA safety (top) and the Vang safety (below).

    Installing the safety is a fairly simple process. There are two options: one involves using a Dremel cutoff wheel and the other involves a gunsmith driver. Using either method, it is a good idea to place the shotgun in a padded vise. The receiver around the safety should be masked off with heavy tape to prevent possible damage. Lock the bolt to the rear so that the parts underneath do not fall into the reeiver.

    Using a Dremel, cut a cross slot into the head of the safety screw. Be careful not to cut down too far or allowing the wheel to either cut through the screw head completely or chattering onto the receiver. Hopefully if it does slip the mask will protect your receiver. Once the cross slot is cut, use a driver to remove the screw as normal.

    If you decide not to use a Dremel, get a gunsmith screwdriver with a good quality edge that is sharp and clean. Using the padded vise to hold the shotgun in place, push down solidly on the screw while at the same time backing the screw out.

    Once the screw is out, remove the safety button. There should be small metal backing plate underneath. It may be stuck to the bottom of the safety, so check if you don’t see it. It will be the same size as the safety button and will have 5 holes in it: One pair each at the top and bottom of the plate, and one in the middle. This plate prevents wear on the dimples on the underside of the safety button, which allows the safety to slip back on after the shotgun is fired. It may be a good idea to place a small dot of grease on the safety detent ball bearing to hold it in place in case the shotgun is bumped. Next take the new safety and backing plate and put it in place, using the central hole to line up on. ETA includes a replacement hex screw to replace the one-way factory screw. You may want to add some LocTite to the threads on the screw for insurance. Otherwise, just screw the safety in and you’re done.

    View of safety port with safety removed. Silver ball is the safety detent. Bolt locked to the rear, safety mechanism "ON."

    Safety installed, "pointed" up.

    Safety installed, "pointed" down.

    The bolt handle from ETA is available here:

    The safety can be ordered here:

  10. #10
    Join Date
    Aug 2007

    Nordic Components Speed Bolt Operating Handle for Mossberg

    Speed Bolt Operating Handle for Mossberg

    Made from 416 stainless steel, the Nordic Components bolt knob is a larger replacement knob that simply drops right in and requires no fitting or adjustment. It is case hardened and Melonite finished in a flat black that matches the black finish of their other products.

    The Nordic knob is extremely light and it feels as though the knob is manufactured from an aluminum alloy. Some 930 users have expressed concern over the heavier replacement bolt knobs slowing the bolt down during long strings of fire such as during 3 gun stages when the shotgun cannot be cleaned. If that is a concern, you can now have a solidly built steel bolt handle that feels light enough to be aluminum alloy.

    Gun Connection The NOB, ETA bolt knob, Nordic knob, and OEM handle

    Relative lengths of knobs

    The surface is textured in a large cleat pattern. The cleats are large enough to provide good surface area for manipulating the bolt. The terminal end of the bolt handle is a large diameter hollow barrel type shape, and helps to lighten the weight even though it is steel. Although the bolt knob is hollow, it has resisted denting well and is solidly built.

    The edges of the handle are radiused down, so there aren’t any sharp edges. It is slightly longer than the factory handle, and provides a far larger area for the user to find and get a grip on during normal bolt manipulation and more importantly, during malfunctions.

    The Nordic handle is a significant improvement over the factory OEM, and if you like the large barrel type knobs the Nordic is a very good choice.

    The Speed Bolt Operating Handle is available directly from Nordic Components:

  11. #11
    Join Date
    Aug 2007
    Sidearmor Forward Shell Carrier

    The Sidarmor Forward Shell Carrier is marketed by Sidearmor for their M4 rail assemblies. However, because it fits any Picatinny rail, it works just as well on the Aimpro Tri-Rail.

    The carrier is a simple three piece assembly consisting of the carrier body, clamping bar, and crossbolt. The carrier body holds two shells in machined recesses in the clamp body. The body is machined from aluminum and has a matte finish that resembles Parkerizing or phosphating. The clamping bar is also aluminum.

    Underside of the carrier. The recoil lug is visible on the near end of the carrier.

    The underside of the carrier uses not just the crossbolt but also a machined recoil lug to engage the cross slots on the Picatinny rail. This helps to hold the carrier securely in place during heavy recoil, such as when using slugs or heavy loads.

    The carrier allows the shooter to put two rounds on the shotgun in a low-profile rail clamping unit. The carrier orients the shells horizontally, and sits very closely to the rail. The carrier can be positioned on the side rails at either the 3 or 9 o’clock position, although there is no reason it couldn’t be positioned at the 6 o’clock bottom rail if desired.

    Depending on how the individual prefers to run their gun would determine which side the carrier would be mounted. If you do your combat reloads over the top of the receiver you may want to mount the carrier on the right side of the gun. If you load the chamber from underneath it may work better on the left.

    Due to the carrier’s aluminum construction and horizontal orientation, some means of retaining the shell in the carrier is needed. In order to do this, Sidearmor uses two spring-loaded ball bearing detents in the forward edge of the shell slots. Slight pressure from the springs push against the ball bearings. These in turn push against the side of the shell in the slot when it is pushed into place.

    The carrier installed on the rail. The two silver dots are the ball bearing shell detents.

    The carrier is intended to hold the two rounds in place by pushing the shells into the carrier until the rim comes into contact with the body of the carrier. The rounds cannot be pushed any further at this point.

    Rear view of the carrier and shells. Note how rims overlap the rear of the carrier.

    As the shells are pushed into the carrier, you will feel the slight resistance from the detent as the shell is pushed over it.

    View showing shells inserted with top round about to engage the detent.

    The Sidearmor Forward Shell Carrier is available directly from Sidearmor:

  12. #12
    Join Date
    Aug 2007

    Mini update

    Mossberg has had essentially three versions of the barrel for the 930 SPX.

    The first was the short LPA front sight tower, the second was the short LPA tower on a welded pedestal, and the third has been a thicker profile barrel and a taller LPA sight tower. The first two are fairly straightforward. However the third has actually had a few versions as well, and I don't know if these are intentional or just a convenience issue.

    The third generation barrel as I said typically has the tall LPA sight tower; that said I've also seen the thick barrel with the short LPA sight. I don't know if this is just another weird move by OFM, of if they are using up the remaining stock of short sights similar to the way that Colt will put out some ARs that don't really fit their type patterns because they are using up the remainder of some small parts that have an excess of.

    Another distinction is the gas cylinder spring. The old versions had blue springs, although some early springs were black. The newer versions have red springs. Again, since this is OFM you will find new production guns with the thick barrel, tall LPA sight tower, and blue springs.

    Here are some pics of the first gen barrel, and two versions of the third gen.

    L to R: Third gen tall sight, third gen short sight, first gen short sight. Barrel thickness is different as well.

    Third gen and first gen barrels with different barrel thickness.

    Taller sight found on third gen barrels. Note position of roll pin and taller front sight ears.

    Comparison of first gen barrel and sight and the third gen barrel and sight. Note that the taller third gen sight has the roll pin in a different location, and the gap between the sight blade and barrel on the first gen sight arrangement to the left. This is due to the taller third gen sight.

    Side by side view of the first and third gen sight bodies.

    The new heavier profile barrels have created issues with the Nordic clamp assembly. There are two ways to resolve this. First, you can contact Nordic and send the clamp back to them for adjustment if you already have one or you can specify that you have a new barrel when you order one so that they can make the adjustment before they ship it to you. The second way is to make the adjustment yourself. Here is how I did it-

    I took an 11/16" Craftsman socket, put it in the barrel channel of the clamp halves, padded the jaws on my vise, positioned the barrel section of the clamp in the jaws, and then clamped it down. I did this slowly, applying even pressure to very gently squeeze the outside of the clamp body down around the socket. After a couple of progressive attempts, I got the bend right and the clamp ears fit around the socket perfectly. I then test fit the clamp around the barrel and mag tube extension body. My clamp now fits the newer thick profile barrels.

    The procedure really isn't hard at all, and as long as you are careful with it and don't gorilla grip it there won't be any problems.

  13. #13
    Join Date
    Aug 2007
    I get asked a lot for what to look for when getting a new 930 SPX to minimize the chance of malfunction. Here's the list.
    If you're getting one, make sure you can check it out first. There are a few things you need to check out first.
    Check the barrel. The latest gen is a heavy profile, like the 590A1.
    The front sight should have tall ears, and the roll pin is in a different location than the early models. The first gen was a low profile FSB, the second gen is simply a first gen on a welded pedestal. The barrel early in my post is a first gen. The later barrel (not the ported one) is a third gen. There is a side by side at the end of the review.
    Make sure the front sight is top dead nuts centered, not canted.
    Make sure the forearm retainer isn't broken.
    Make sure the extension isn't bent or dented.
    Make sure the mag tube spring isn't too long. If it is, it will prevent the first round from being released from the mag tube if the mag tube is at full capacity.
    Check the end of the mag tube (not the extension, the actual mag tube) for burrs. You may need to chamfer the opening slightly.
    Some of the transition areas on the extensions are rough as well, or too long. They will bind up the followers.
    Take the barrel off and look at the spring on the gas piston. You should be able to see it in the witness hole. The first gen springs were blue, and there were some that were black. The newer springs are red. They will let you shoot lighter loads, although some (including myself) never had a problem with lighter loads with the blue and black spring.
    The forearm should have a sling button screwed into it at the bottom up close the mag tube extension.
    The bolt knob should be a round version, very similar to the ETA and Nordic models.
    Make sure that the short screws are in the front of the rail, and the long screws in the back. They are coming from the factory with thread locker on them now. Make sure they aren't overtorqued and fall out.
    Look to make sure the FCG doesn't have a lot of movement, or sits in the receiver at an angle.
    Lasly, make sure the FCG pins are flush with the outside of the receiver. They shouldn't be below the level of the receiver; I've seen somebody who had a 590 pin in their 930. Caused some problems.
    Make sure you clean it well. I mean really, really clean. Mossberg ships their shotguns with a ton of preservative in their shotguns.
    I know this is a lot of things, but it is literally everything I've ever heard of being a problem with a new 930 SPX. I dont' know of anybody who has had more than one or maybe two at the most. Certainly never heard of somebody having several much less most of them. If you got all of them, I dont' know what to say because you are probably about to have the ISS fall out of orbit right on top of you and you are the unluckiest dude. Evar.

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