Pistol caliber carbines

[Stone]

I have been looking around at pistol caliber carbines like the Sig MPX and others. Is it me or am I missing something. There seems to be a good sized fan base for these but for practical purposes I fail to see what it has over an SBR chambered in 556 or 68. Is it just a novelty? To me each tool has to have a purpose. In a self defense situation, if what I have available is a pistol in 9mm or 45 that's what I will use but if I have a choice at the moment I will grab a rifle that has a lot of energy behind it (5.56,6.8 etc.) before I would grab a pistol caliber rifle. I fail to see any advantages it would have in any scenario like conceal ability etc.,etc. Except for a slight weight loss compared to my SBR's I fail to see any advantages. Maybe some of you guys that own these could explain to me what lured you in...

[alamo5000]

Define 'practical'.

I don't have a PCC yet but it's on my short list.

I can shoot a whole lot more, for a whole lot cheaper.

Also suppressed it's super quiet.

For say a night stand gun, if you have a tiny little suppressed PCC for indoors use it would be great. 9mm been dropping bad guys for a long time. .45 ain't no slouch either. People carry these calibers every day for self protection including cops all over the US.

At the end of the day I though think my chances of getting in a gun fight are about the same as me winning the power ball so with that in mind, why not? They just seem downright fun.

The only PCC I have ever shot was a real deal MP5 complete with the happy switch... and man, that was awesome.

I think in semi auto it's still gonna be super fun for a lot cheaper to shoot.

[fledge]

Stone, I’ve had all the same questions.

Best I can make out is cheaper to train with.

I can see something like the Ruger PCC if you need compact/portable, 50 state legal rifle. (Eg. you can’t take a handgun camping to New York but you can take a qualified featureless semiauto).

[PJD642]

I've got both the MPX and the Ruger PCC (purchased the Ruger first). Both of them were purchased with an eye towards being truck guns and having commonality with my G19 for ammo (and mags in the case of the Ruger). The PCC is essentially a larger 10-22 that takes Glock mags if you swap out the mag well (purchase includes both the Ruger & Glock wells). It's a take-down model, so when apart it fits in a decent sized backpack. Mine has been reliable & fun. With the bolt face being slotted into the bolt, there's *hope* that Ruger will eventually come out with bolts/barrels in .40, .357 Sig or even a .45 model. Magazines cost whatever a Glock mag costs near you. There's not that many aftermarket accessories for it yet.

The MPX is lighter in most configurations & takes a lot of AR standard parts. Being a piston/pistol caliber gun the bolt is very fast and really shoves the hammer rearwards. It needs a bridge to keep the hammer from smacking the disconnector and eventually breaking it, so you have to (*should*) buy a trigger made specifically for the MPX. In a pinch you can use a regular mil-spec AR trigger group. Magpul, BCM & other AR grips fit fine. It requires an MPX specific charging handle, bolt, bolt carrier, etc. The magazines are ridiculously expensive (~$55 for a single 30-round Gen 2 mag). The "buffer spring" equivalent is contained in the receiver above the bolt, so it can use a folding or collapsible stock. My 8" barrelled MPX is a "pistol", so with the SB3 brace on the folder I have a shoulder fired gun that fits almost anywhere when compacted. There's a LOT of aftermarket parts for the MPX, with more manufacturers getting in on things every day.

Anecdotally, I had both of them at the range last month during qualifications. People tried them both, and EVERY SINGLE PERSON fell in love with the MPX. The Ruger was ok, but the MPX was a prom queen. It's just a fun, accurate, almost recoil-less little gun that you can't help but smile when you shoot. Does it offer the terminal performance of a 5.56 pistol or carbine (or a .300 pistol)? No. Would I be comfortable using it in an urban environment to get the hell out of Dodge? Absolutely.

I plan on SBR'ing & integrally suppressing the MPX.

Photos of each tomorrow.

[kattman]

USPSA PCC Division has taken off big time, and is driving the fan/accessories market wild. The SIG MPX with it's soft recoil (gas ops) is a favorite. Have three that are SBR'd. The SBR's (8.5" bbl) are exceptionally handy (and fun) on USPSA stages.

[Jerry R]

I took a long hard look at what was available, and decided that if I really wanted (not needed) a pistol caliber AR style platform, I would get something compatible with my Glock 21 - magazines and ammunition. I opted for an AR Pistol instead of a carbine length firearm. I may SBR it, but I wanted something short and handy (and fun).

To respond to the question ... "what lured me in" was the novelty - sad but true. The odds of this old man "needing" an AR platform are pretty slim. And, to be honest, IF that need arises, I'll pull the 10.5" 6.8 SBR out of the safe.

[UWone77]

For AR based 9mm's I find them more plinkers than anything. Sometimes they're a pain to get running as some of them need tuning. LRBHO isn't as common as one might expect from an AR platform pistol carbine.

Personally, if I'm shooting pistol ammo through a rifle, it's going to be an MP5 or something designed specifically around the cartridge. I also like the KRISS Vector and the MPX. Slightly less gassy vs a rifle round as well.... (except for the MPX, sucked suppressed)

[Stone]

Thanks guys! I really appreciate the honest answers. At this stage of the game I am learning to separate my wants from needs and dislike things collecting dust because I had an itch that wanted to be scratched. In that situation I usually end up selling stuff at a loss, which sucks. With that said, we work hard for our money and its nice to have the freedom to spend it on what we want, I get it. FWIW they do look like fun to shoot! Sounds like the Sig MPX is at the top of the list as one of the better options as far as reliability. With the longer barrels how do 9mm defensive rounds hold up under the higher velocity's? Doesn't seem to me, that say a 135g Tactical bonded round would act the same through a 16" barrel as opposed to a 4" barrel on my Glock. I wonder if terminal performance is compromised or increased?

[Jerry R]

With the longer barrels how do 9mm defensive rounds hold up under the higher velocity's?

I can't speak to the FPS changes on a 9mm ... but at the last shoot with Grif we chrono'ed 45ACP comparing 5" 1911 to 8" AR Pistol. Gained between 100 and 110 FPS. Having said that, I would "assume" there is a law of diminishing returns on the 45. At some point you will have squeezed all you can get out of it.

[BoilerUp]

I've got a two-stamp MPX that's a hoot and what I keep close by for things that go bump in the night. 147gr subsonic Gold Dots should get the job done. What I like is you get the same ergos as the AR in a *slightly* more compact package with minimal recoil. The only things I don't like about the MPX are that it is heavier than I would prefer, the mags are expensive (but excellent), and the stock trigger is horrible and you limited aftermarket options. I just put a Wilson Tactical TTU 9mm in it last night. Ergos and LRBHO are, IMO (which isn't worth much) superior to the MP5, but an MP5 (clone) is probably my next major firearms purchase because....MP5!

But my favorite thing about the MPX is the Taran Tactical videos:


https://www.youtube.com/watch?v=VduyKQUEhyg

[UWone77]

I think performance wise the MPX is about the same as a MP5. I just prefer the MP5 in the iconic looks dept. Plus I just ordered a KAC rail for mine.

I think what's really missing is the full auto aspect of pistol carbines. I found the MP5 obviously more enjoyable to shoot and train with when we had department MP5's. If I ever move to a free state I'm getting a F/A MP5 setup.

Someone needs to also come out with a 10mm foldable carbine. Sort of like the LWRC .45 sub gun they previewed at SHOT 2016

[MoxyDave]

Oh man I forgot about that LWRC SMG-45. I was immediately interested after reading about it. I just did a little poking around, and it still appears to be vaporware.

I find it baffling that a company can miss such a golden opportunity. They would sell a zillion of these things if they just got off their collective asses and finished it.

Here's some links and photos just because:

Initial release notes from LWRC employee (https://www.mdshooters.com/showthread.php?t=192719)

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Killer 3D model rendering:

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[Stone]

Ahhh the SMG debacle... I am/was a mod on the LWRC forum and it turned into a non stop bitch fest about "when is the SMG coming out"? Unfortunately some folks don't when to reel it back it when asked nicely so we had to nuke a few folks over there. I am still in touch with a few guys over at LWRC and I will send them an email to see if the SMG will ever materialize. Definitely like the 10mm options...

[Stone]

A little bird just told me that the pistol version of the SMG "should" be out at shot show next month (2019) and the regular SMG should follow later next year.

[UWone77]

I imagine they are just trying to get it "perfect." I know that's been the delay with the Cross Machine 9mm sub gun. Gotta get the gun to run with all kinds of ammo, and tune it.

I'd rather wait till LWRC gets it right vs something that looks good, but doesn't run consistently.

[alamo5000]

I imagine they are just trying to get it "perfect." I know that's been the delay with the Cross Machine 9mm sub gun. Gotta get the gun to run with all kinds of ammo, and tune it.

I'd rather wait till LWRC gets it right vs something that looks good, but doesn't run consistently.

Part of the reason why I haven't prioritized a PCC is simply put I am not seeing or finding anything that I like and that I know will run. The Scorpion, the Sig, none of them have really rung my bell.

I am with you though. I don't want to be somebody's guinea pig.

[MoxyDave]

I guess we'll see, then. In the meantime, if I were in the market I'd probably pick up one of these:

CMMG Banshee 9mm SMG (https://www.cmmginc.com/product/pistol-banshee-300-mkgs-9mm/)

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[prussianfrank]

Merry Christmas to all, I keep seeing this thread pop up in my Tapatalk email so I finally read it, and now I made an account to reply.

The one thing left out of this discussion that is the importance of delayed cycling (or delayed blowback) in PCCs. I'm no professional, take with a grain of salt.

All of this assumes your PCC is suppressed. The primary point of a PCC is indoor shooting.

With a PCC, I vote to always go with a delayed blowback gun...never a straight blowback. Straight blowback isn’t terrible, but not ideal either.

Straight blowback is louder at the ejection port and (in an AR platform) requires a heavier buffer and heavier overall weight (no bueno, but a heavier buffer can help balance a heavy suppressor on the front end). A stout buffer spring is also helpful. The benefits of a straight blowback is that its simple, cheap, and reliable so long as you don't beat your trigger group to hell in the process. Have a good "ramped" bolt and appropriate trigger. Keep the ramp polished and lightly greased, not oiled. Wipe down the bolt after every outing (I never keep my sh-- clean). Take an air compressor to the trigger group regularly. Don't use a fancy precision trigger. Use a stout group that has a good enough feel to you. Pick up on the timing of the girl, and get into a rhythm when shooting. But I don’t like it cuz of the loud bark out the ejection port (even when suppressed). These have been called the highpoint of the AR pcc world, and for good reason. I really got sick of my first AR stright blowback 9mm because the recoil impulse was so sharp. I was shooting a sharp angry b---- rather than a pleasant mellow b----. It's not that the recoil was strong, but the impulse was sharp. Hard to explain. But if you shoot so much in a day that you get sick of it, and then keep shooting a whole lot more that day, you will pick up on these things.

A DI or gas impingement action is the nicest to shoot, but like all DI systems are dirtier in the action and can grit up the locking lugs. For "normal" people, this is usually never a problem. I've never seen a 9mm DI gun, but I've read discussions of them. 10mm is good with DI because has heavy charge weight. 45ACP is apparently doable, but I have not done it. And 45Super is..imo…the most ideal PCC cartridge. You can put a ton of (clean slow burning) powder in a 45Super and get some righteous velocities in longer bbls (think 6-10” range). The benefit to DI is that it keeps the bolt locked closed longer and you don’t get that “loud bark” out of the ejection port. Also, it smooths out the recoil impulse (unlike straight blowback). People overlook this and sometimes never even notice it, but the pulse curve of the recoil impulse is so important to the feel of the weapon (and followup shots). I think the MP5 has the best recoil impulse and the impulse is the reason everyone likes it…even if they don’t realize that’s the reason. But MP5 is NOT gas operated. Also, a gas operated action can take a lot of effort to refine and make perfect, i.e., dialing in your exact charge weight and gas port pressure, adjusting the gas block possibly (if you have an adjustable gasblock on a PCC), adjusting the buffer and buffer spring. Then again, you don't have to tune the rifle to the nth degree.

Turning to non-gas operated delayed blowback (such as radial or roller or vector or whatever), these are a good happy medium ground. They don’t blow carbon on the action like a DI but they keep the bolt face closed (not fully “locked”, tho) and reduce the bark from the ejection port. Win-win. If the delaying mechanism is well done (e.g., MP5), you can get a real nice recoil impulse that makes follow up shots soooo sweet. This is why all the super duper commando whatevers liked the MP5 (so I've read). One downside is that you can’t tune this cycling to the same extent you can tune gas operated cycling. For most people, that is a benefit because it also mean its not as finicky with different ammo. The more you tune something, the more finicky it will be. Some ppl don’t love tuning the cyclic rate and impulse curve of their rifles / PCCs. I think it’s fun, but I only ever shoot at paper enemies.

https://en.wikipedia.org/wiki/List_of_delayed-blowback_firearms

PS. Technically, gas operated is not "blowback"....it's neither straight blowback nor delayed blowback. But it has some of the desirable effects of a delayed blowback because the unlocking of the bolt delays the cycling of the action.