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View Full Version : Superlative Adj. Gas Block



FortTom
3 November 2017, 21:41
Has anyone used one of these? Sold by Faxon and a few other retailers. It's adjustable, but in a different way. Gas is restricted, but excess gas vents out the front of the block. Also negates corroding the metering screw, by not blowing all of that excess gas and carbon back into it.

I was going to buy a Syrac, but it appears their out of business now, and the retailers that have some, didn't have one in .625". This will be used with my "light weight" project which will use a skeletonized BCG. I was going to try to adjust any over gassed problems with spring rates and buffers, but after being beat with an ugly stick by several folks to drive some common sense into me.[bash]

I began to see the error of my ways and ordered the block which will be mounted to a Faxon 16 "pencil" barrel.

It will be a little while, due to some logistical problems, before assembly, so I thought some of you folks might have some input on it. It's bought and paid for, so I pray I don't hear any "horror" stories" Not much in the way of reviews on the 'net so I thought I'd troll the forum for some info.

As always, thanks ahead,

FT[:D]

Slippers
3 November 2017, 22:37
Sorry to say but I have had a poor experience with one. Broke on the first trip to the range. No customer service, they wouldn't respond or replace it.

The vented settings also did not work.

SLR is the only adjustable gas block I'll use.

Default.mp3
3 November 2017, 23:51
SLR is the only adjustable gas block I'll use.You should buy MicroMOA's IP, yo.

fledge
4 November 2017, 09:30
Slippers beat me too it. I’ve not had a break but the bleed-off just doesn’t work for me. You can close the port but with less refined adjustments compared to the SLR. BTW, Superlative made the Syrac.

I’m moving away from adj unless I plan to suppress a rifle often. I also won’t buy a low mass BCG again. That’s probably the place to have the most sense beat into you. Hahaha

BoilerUp
4 November 2017, 09:59
Has anyone used one of these? Sold by Faxon and a few other retailers. It's adjustable, but in a different way. Gas is restricted, but excess gas vents out the front of the block. Also negates corroding the metering screw, by not blowing all of that excess gas and carbon back into it.


Another vote for the SLR Sentry series from me. I've never heard a good explanation of why you'd want to "bleed off" gas. Gas that isn't needed to cycle the action should be put to use to propel the bullet. That's kind of the whole point of creating the gas in the first place.

FortTom
4 November 2017, 13:01
Another vote for the SLR Sentry series from me. I've never heard a good explanation of why you'd want to "bleed off" gas. Gas that isn't needed to cycle the action should be put to use to propel the bullet. That's kind of the whole point of creating the gas in the first place.
My understanding is this. The AR's were designed to let X amount of gas bleed out of the barrel, down the gas tube and to cycle the bolt. You mess with the system too much, such as using a lightened bolt, and X equals too much, "over gassed", and bad things start to happen. So, you adjust the amount of gas that passes through the block and tune it until everything works just right. Not a whole lot difference than adjusting the gas for a suppressed weapon. Different issues, but adjusting gas for same reason. With a can, you get away from the specs that the weapon was designed for. Over simplified, but I think I'm pretty close.

Correct me if I'm wrong...just don't beat sense into me with a stick...[:D]

FT[:D]

UWone77
4 November 2017, 13:06
Unless you have an overgassed barrel and/or shooting suppressed, I would just stick with a non-adjustable.

FortTom
4 November 2017, 13:11
Unless you have an overgassed barrel and/or shooting suppressed, I would just stick with a non-adjustable. That was my initial plan. However, when I've called vendors for their opinion, if I'm going to use a "skeletonized" BCG, they have all recommended an adj. block.

FT[:D]

BoilerUp
4 November 2017, 14:40
My understanding is this. The AR's were designed to let X amount of gas bleed out of the barrel, down the gas tube and to cycle the bolt. You mess with the system too much, such as using a lightened bolt, and X equals too much, "over gassed", and bad things start to happen. So, you adjust the amount of gas that passes through the block and tune it until everything works just right. Not a whole lot difference than adjusting the gas for a suppressed weapon. Different issues, but adjusting gas for same reason. With a can, you get away from the specs that the weapon was designed for. Over simplified, but I think I'm pretty close.

Correct me if I'm wrong...just don't beat sense into me with a stick...[:D]

FT[:D]

FT, you're right but I think you missed my point. I totally get AGBs and have them on most my ARs anymore. My point was that the SA system creates a 3rd gas path. To be clear, the first gas path is down the barrel pushing the bullet, the second is down the gas tube to cycle the bolt, and SA appears to add a third path out through the bleed off whereas traditional AGBs simply restrict the second path. I'm of the opinion that if you have excess gas cycling the action, use an AGB to restrict that path and keep the gas for its original intended purpose to push the bullet.

Note that if you are just a touch overgassed you can slow the action down a bit by adding to the reciprocating mass (either the Bolt Carrier or buffer). For example, if you are overgassed and running a semi-auto bolt carrier and standard carbine buffer, you can simply add a full auto carrier and / or heavy buffer. If you have to add more than ounce and / or feel the need for a heavier spring its worth considering an AGB. Conversely, if you go the other way and start taking weight out of the system (e.g., lightweight BCG) you'll almost certainly want an AGB. I have two rifles with lightweight BCGs (one 5.56 and one .308) and both run AGBs and are great shooters.

FortTom
4 November 2017, 16:20
That's exactly what I'm doing, BU. This whole build has been about weight (light) from it's inception. Lots of 2A and V7 parts. Super light barrel, handguard, upper receiver, buffer tube, BCG, controls, etc.

So "lightweight" has been the main objective, assuming everything works alright, and that's how I'm hoping it ends up that way. Just have to hold my breath and wait and see. Meanwhile I'm going to knock down this six pack and contemplate some more...[wow]....burp...er.. excuse me.

FT[:D]

GOST
4 November 2017, 16:42
I’ve also had good luck with the SLR.

alamo5000
4 November 2017, 16:49
I can't compare because I've never used anything else but +1 on SLR. Flawless in multiple years of use. Probably carbon welded by now but I don't want to adjust either of them.

BoilerUp
4 November 2017, 18:07
That's exactly what I'm doing, BU. This whole build has been about weight (light) from it's inception. Lots of 2A and V7 parts. Super light barrel, handguard, upper receiver, buffer tube, BCG, controls, etc.

So "lightweight" has been the main objective, assuming everything works alright, and that's how I'm hoping it ends up that way. Just have to hold my breath and wait and see. Meanwhile I'm going to knock down this six pack and contemplate some more...[wow]....burp...er.. excuse me.

FT[:D]

You just missed a sale at SLR but this is pretty good: https://www.righttobear.com/SLR-Rifleworks-Sentry-7-Set-Screw-Adjustable-Gas-B-p/sa7-sm.htm

My LW build has a Voodoo pencil barrel, Voodoo LW BCG, and a 2A handguard and some miscellaneous other V7 parts. The SLR Sentry let me tune it nicely and it's a lot of fun to shoot.

https://photos.smugmug.com/photos/i-k52m97v/0/d51bb54e/L/i-k52m97v-L.jpg

FortTom
4 November 2017, 19:38
BU, with the exception of the MFT stock, we're pretty much on the same page, with this build.[:D]

FT[:D]

UWone77
5 November 2017, 18:37
BU, with the exception of the MFT stock, we're pretty much on the same page, with this build.[:D]

FT[:D]

Heh, I really hate MFT stuff. Airsoft worthy.

Other than the minimalist, I can't think of one quality product they make.

ChattanoogaPhil
23 June 2018, 10:00
Thinking about a SLR Sentry 7 set screw adj gas block to fit under a Midwest Industries Combat handguard. This is just to tame down an overgassed carbine. No suppressed shooting... at least not at this time. Reading some of the positive remarks here I'm guessing that folks using SLR adj are still generally pleased? Cons?

Also considering a Back River Tactical "port" that somehow installs in any regular non-adjustable low profile gas block. Seems simple enough which might serve my purpose of reducing gas a bit rather than fine tune. Any experience with these?

Slippers
23 June 2018, 10:37
Both work well. I use slr whenever I need adjustable gas and have used the brt ports, too. Brt also has some new gas tubes that do the same thing, and are easier to use (for obvious reasons) than the port screws.

fledge
23 June 2018, 12:04
The BRT inserts can be purchased with a kit for tapping the gas block. Easy install. I’d go that route if you don’t have a pinned device already. Clint recommends difference sizes depending on your application.

I have their gas tube and it works too but still in prototype mode. They are unsure how much erosion the gas tube hole can take.

The SLR gas blocks are good too if you need an adj.

ChattanoogaPhil
24 June 2018, 03:38
Thanks guys.

Anyone ya know offer a WEVO discount code for a Sentry 7?

BoilerUp
24 June 2018, 06:50
Thanks guys.

Anyone ya know offer a WEVO discount code for a Sentry 7?

I've got SLR Sentry AGBs on most of my builds now and am very pleased with them.

I'm not aware of a WEVO discount code. SLR just had a Father's Day sale, and I'm sure they'll have a 4th of July sale in a week or so. Ordering direct from SLR is good as customer service is excellent. Another great source is Strong Side Tactical which has them for a few bucks off, free shipping, excellent customer service, and ships very quickly. Looks like the best deal right now would be Brownells, as they have an active 10% off and free shipping coupon code.

ChattanoogaPhil
24 June 2018, 08:52
Thanks again.

Forgot to ask... for a barrel having not yet been dimpled is there any reason to select screw spacing of one over the other, .4 vs .45?

Mecha_Arms
27 June 2018, 19:30
Thanks again.

Forgot to ask... for a barrel having not yet been dimpled is there any reason to select screw spacing of one over the other, .4 vs .45?

The .45 is for Larue barrels. If you don't have the barrel dimpled yet, just get whichever one is cheapest.

Evintos
30 June 2018, 08:35
SLR is having another sale right now on gas blocks. 15% off.

https://slrrifleworks.com/index.php?route=product/category&path=57&limit=100