Being an old guy who had been around even long before the AWB hit, I well remember shooting the A2 stock.  Rifle length stocks just always seemed to feel better when shooting a gun. Even with 16" barreled 556 uppers.

I started thinking, why has no one commercially made any heavy pistol caliber buffers in rifle length for anyone wanting to use a rifle length stock on their guns?

Yes, I know, a lot of folks prefer to keep their PCC's as short as possible, and I understand that.   Heck, I have some that I want to keep as short as possible too.  

But, not ALWAYS.  The only thing available for PCC buffers are carbine length.

There are times when a rifle length PCC makes sense.  Especially those like me that enjoy shooting suppressed who want to tune their gun the best they can or those who shoot really hot/heavy loads and calibers.

About a year and a half ago, I made a 10mm carbine for deer hunting that used an A2 tube and modified a heavy Kaw Valley 10oz buffer into a 12.5 oz rifle buffer.  Put a piece of foam over the tube similar to the old Ace skeletons and then threw a Gearhead works Tailhook on it because I had the parts laying around and so I wouldn't have to buy a new stock.  I may have even made a post about it here, but if I did, I couldn't find it and it's been a while since I logged in.  

The heavier buffer sure helped tame the hot loads that I had worked up.  Ejection went from about 15 feet into the next zip code and lower earth orbit, down to about 8-1/2 or 9 feet now.  While still a very healthy ejection distance, has nonetheless helped reload the brass more too.  I'll also say it's a lot easier to reload when you can find it.

Plus, the longer recoil/bolt cycle with the rifle stock, sure makes it more enjoyable and easier to shoot.

On top, you can see the extension that I put onto the KAW VALLEY buffer to make it a rifle length.  I also threw in a flat coil 308 buffer spring in there too.



To help add some more preload on the spring, I added a longer sleeve on the buffer too.





As for my 45 upper, it's an integrally suppressed design that I made a couple of years ago.  I've always liked the gun, but now that I've put an A2 stock on it, the gun just wants to be shot.  At the end of the day, the longer bolt movement helps keep the gun shooting very flat.  Now that I modified an Armaspec stealth buffer to work in the gun, it also helped quieten it down more too.  I think in keeping the bolt closed a hair longer than it was before.

The armaspec stealth buffers generally have a guide rod that protrudes into the rear of the bolt carrier.  But, pistol caliber bolts typically all have added weights in the rear of them that would not work with the armaspec guide rod.  So, I did what any red blooded American would do and redesigned it to work how I wanted it and machined a piece of steel on the lathe.

Original armaspec


My rifle length version


With the longer rifle length buffer tube, had enough room to make an extended steel buffer that does NOT need to protrude into the back of the bolt.

Here's as far as the buffer will move back over the guide rod.  Now it'll work with any pistol caliber bolt I want to put it behind.



Fully compressed:





I know that not everyone will like a full length rifle stock on a PCC, and that's fine with me.  It's mine and I made them how I wanted them.  At the end of the day, the important thing to me is it's so quiet that you can hear the disconnector resetting and the empty brass bouncing across the gravels and the muzzle barely moves at all when you're shooting it.  I'll add a short video and you can watch how much more stable the muzzle is with the rifle stock when compared to using the collapsible stock.  So, as they used to say "the proof is in the pudding".  Using a rifle stock and heavy rifle buffer setup can be beneficial for pistol calibers too.

Neat.

The A5 buffer tube length generally provides a cost and performance effective middle ground with adjustable stock capabilities.

MHO, YMMV, etc.  Be well.

For me and I imagine most of the market, a PCC is supposed to be a compact gun. 9" barrel or less suppressed SBR would be the only way I get into PCC's.

 Most of the market is not ARFCOMers.  16" PCCs sell quite well, w/ new fixed stock models being introduced all the time to take advantage of existing pistol mags.  I sell several SUB-2000s every month.

I can see where a rifle length buffer system would help with PCC's. And it wouldn't be hard to add more weight to one either. I have weighed all of my rifle length buffers and they are between 5.2 and 5.5 ounces.

5.5 ounces is the minimum buffer weight for a 9mm blow back upper. And you can use the same spacer with a rifle buffer that most use with a PPC carbine length buffer.

I certainly understand that and can agree to a large extent.  Most of my PCC's are compact and suppressed.

But, there are times, such as my reasons above, where I want to squeeze as much performance out of a gun as I can.  

Like, the 10mm.  As I said, I'm getting at least 400 fps (and more) with the carbine barrel than I can get out of a short barrel while shooting out of the same box of bullets.  So, for hunting whitetail and things, there was no reason why I would've wanted to use a 4 or 5 inch barrel.  At that point, I would've just rather bought an XD or Glock.  But, with the carbine, I have better sights, option for a scope if I wanted.  Or better sight picture, much better velocity/performance.  

As for stock length itself, even with the collapsible stock, I keep them extended all the way out when I'm shooting because I have a long length of pull anyway.  So, I'm not really handicapping myself more than about 2 inches while using a rifle stock where that is concerned so that's only going to be marginally longer if honestly comparing the two.  If anything, the rifle length feels even better to me when shouldered.  Everyone is different though.

As for the 45 build, it's a 4.5" barrel hidden underneath of there, but the suppressor is 16 inches long to meet minimum lengths after pin/welding so I wouldn't have to double stamp it, but adding and using rifle length parts helped get the most performance out of it as possible.  It's quite.  It's very accurate and stable shooting.  By adding the rifle length buffer and stock, the balance improved more to the rear and it's not muzzle heavy anymore.   Again, better sight radius.  

I don't disagree that most people getting into PCC's are wanting short.

But, not ALWAYS.

There's a lot to be said for a gun that's tuned and geared towards what you're wanting to use it for.  

But, you can't just go out and buy a heavyweight PCC rifle length buffer because they're ignored by the market and no one makes them.  Everyone has collapsibles on their PCC's because, well, that's what they can buy for their PCC's.  I just don't limit myself to what I can buy.  If I want to try something different, I will even if I have to make it myself.  And for these two instances, worked out to the good.

There are a couple of companies (RRA being one of them) that make inexpensive carbine to fixed stock delrin spacers. They allow you to drop the spacer into the rifle length buffer tube and use carbine springs and buffers.

Yes those spacers will work to allow the use of a carbine length buffer. BUT it defeats the purpose of what the OP is doing since those spacers limit the travel for use of carbine buffers and springs. A rifle length buffer system will have a smoother recoil impulse. And the OP is after a smoother recoil impulse.

I fully understand most people aren't arfcommers. Sub-2000s are cheap. It's like braces. I bet the majority of people bought a short AR due to walking into a gun store (wanting an AR), and seeing a short AR on the wall that had a brace. They wouldn't have done a factory SBR, but a short "pistol," heck yeah. I am not saying what the OP is doing isn't awesome or shouldn't be done. I was just addressing his thread title. That's what I honestly think it is.

Agreed. I think you are in the minority, which isn't a bad thing. You are just trying to get everything out of a 9mm build you can. I applaud that!

@spiderboy, I'm sure I am in the minority.  No doubt of that.  And we don't disagree.

But I'm certain there are others that like to tinker and improve things where they can which is what I was doing.

At the end of the day though, options are always good.  And that's not something we have in this regard.

@davetoll, I had forgotten about the rifle tube inserts because they just allow you to put your carbine buffer into a longer tube.  I was referring more to actually making or using heavy rifle length stuff.

I am not sure what anyones' experience levels are, but I've been shooting AR's since the late 80's and suffered through the ban years too.  During the ban years, just about the only thing most companies would sell was the rifle length stocks, but they really were a lot softer shooting than their shorter stocks.   Later in the ban years there was some pinned open fixed collapsible stocks but I'm sure that wouldn't fly in this day and age.

But those spacers would still essentially be carbine specs despite whichever stock or tube you had on it.

The rifle length stuff I'm referring to seems to be less recoil (something that pcc's seem to struggle with with most being blowback) and are just more pleasant to shoot.  Rifle length just changes the dynamics of the gun for the better.  Slows the bolt travel down some more.  Etc.

I'm not saying that PCC's are abusive to shoot or anything.  I have other guns that are not fun to shoot at all.

But, by using the rifle length stuff just improves their shootability.  Especially for smaller folks and women and children.  Or, I guess fat old guys like me.

@JohnA4

Are your 10mm and 45ACP uppers blowback or DI? Guessing blowback, based on the need/desire for the heavier/stronger buffers, but wanted to confirm.

@JohnA4

Good write-up!  

Good job with the adapter weights to allow the KVP and Armaspec to work with A2 PCC, especially the Armaspec.  Those captured systems usually cause the blowback mass of a PCC to be significantly underweight due to the need to remove the bolt mass for the guide rod.

I see you also discovered the same thing I did - more mass in a semi-auto blowback slows the action, reduces felt recoil, reduces ejection distance, and as a result will reduce wear on all the parts.  I'm an advocate of using 11oz buffers in 9mm blowback, and 9mm can cycle with much more than that.  In my testing, a 2.5" barrel cycled a 37.5oz total blowback mass reliably with 115gr factory ammo.  The cartridges just dribbled out, but it worked.

PCC recoil can also be reduced by using a combination of hydraulic buffers and supplimental mass to slow and cushion the action, which was the basis of my "gentle recoil project".  My combination makes a 9mm simple blowback feel about the same as a CMMG Banshee from the perspective of felt recoil.  A longer buffer tube is used (8.5"), but not as long as the A2.

You may find these interesting:

A2 tube on a 9mm PCC

Overmass Project - 9mm PCC - 37.5oz

“Gentle Recoil” Part 1, 9mm AR Project (with testimonials – it really works!)

ETA: as an FYI, 9mm blowbacks don't need .308 or XP springs.  It's a myth and a bad practice unless you are purposely trying to force the bolt back into battery faster for some very specific reason.  They can cause a number of very significant problems that are fixed by switching back to a standard AR15 spring.  Plus, recoil will feel better with the standard spring.

The case against .308 recoil springs in a 9mm AR

(yes, I know some of your stuff isn't 9mm, but most of this applies to larger blowback PCC calibers as well. The biggest difference is that they require more mass.)

JohnA4, I get it that you are building for harder hitting PCC calibers.

My mention of the delrin spacer was for the benefit of the predominate non-machinist 9mm PCC crowd who might want to go old school and use a fixed stock. For them, the same amount of mass, moving the same distance in either buffer tube should be the same recoil.

I decided to play around this morning and took my 9mm upper and stuck it on a lower with a rifle buffer system. I did put the spacer on the end of the rifle buffer spring. This is any easy swap for those that want to do it for 9mm blow back uppers. All you will need to do is add some weight to the rifle buffer. My rifle buffer weighs 5.2 ounces and the 9mm buffers that Colt and CMMG uses is 5.5 ounces (bare minimum weight). Now adding enough weight for 45ACP or 10mm might take some ingenuity like JohnA4 did.

Attached File

@towerofpower94 Yes, all of my PCC's are direct blowback.  They're not DI and whatever cmmg calls their hybrid AR style bolt is.  I'm not saying what I have are better, and truth is I've never used any of the newer types though I could certainly appreciate less weight at the end of the day, but yes, keeping the bolt closed longer with heavier weight buffers and springs in this design is both necessary and common.

@chumpmiester  did it change the way the gun felt to you?  Feel smoother or better? What did you think about it?

@Droppoint I have played around with PCC's for a very long time.  Even during the awkward and stupid "PCCs are obsolete" phase that many people went through for a while before realizing that there are many pistol caliber ammo that suppresses well is still perfectly useful for a lot of things.  Especially HD.  But, I digress.

One of my earliest PCC's was a 9mm upper that I eventually form 1'd an integral suppressor for.  I ported the barrel similar to the Delisle and MP5 SD and such, and I too have tried a lot of different springs and buffers in it.

I didn't keep the 308 spring in mine longer either.  Matter of fact, I'm using a 7oz carbine buffer in it, though I am using a flat coil AR spring in it simply because I like them a lot, but it's not one of the 308 caliber rated springs.  Regular (556) AR flat spring.  And for the reasons you mentioned.

With my 9mm upper/barrel being ported, I didn't have as much back pressure or back gassing due to more gas being ported out over the barrel, I didn't benefit from the heavier springs and buffers.  Mine casually ejects brass out about 6 feet or so?  That's using my 165 gr suppressor loads I make so they're really mild anyway.  

When switching from a 5.6 to a 7 oz buffer, I just can't really tell the extra 1.5 oz of buffer weight has made any noticeable difference in anything so I'm not completely sold on it yet.  I was trying to maybe keep the bolt closed a little longer to reduce any ejection port pop but I can't really tell that there was any change in it at all.  

I don't generally notice any port pop at all in the sound levels, but during shooting at dusk or dark, I can notice the occasional flash around the ejection port when the bolt starts moving back.  Much like the occasional 16 inch 556 flash you'll see when shooting after or near dark.  It's not all the time, but would be dishonest to say it doesn't exist.  So, that's what I was trying to tune a little better.

But with my barrel being ported, there is obviously going to be less back pressure or back gassing available and why I am not going heavier buffer or spring in that gun.

So, that's why I have tried so many different things just trying to tune everything to work together.  That's only something time and experimentation will show.  I can appreciate someone else willing to try different things for sure.

The AR45, is really liking the A2 length and the modified/redesigned armaspec buffer.  I don't see any reason to ever change it again.  It's a really sweet shooting gun.

OP, would love to see pics of your Form 1 integral suppressor.

@JohnA4. I only did a test fit to include function checks. I don't have any extra weight to add to the rifle buffer, I want the weight to be at least 5.5 ounces or more.

I believe VLTOR sells a PCC buffer for their A5 buffer system. It is suppose to smooth out the blowback operation a bit.

No ingenuity needed. Just use a mixture of Tungsten weights, steel weights, and aluminum weights to get the weight you want. I have rifle buffers from 3.2 to 9.4 ounces depending on the ammo/caliber I'm shooting.

I agree it is a simple thing to just swap out the individual buffer weights until I get the weight I want. I just don't have any extra weights laying around.

I think Vltor's PCC(9mm) buffer is nothing more than a heavy, stainless A5 buffer that works perfectly in a standard carbine buffer tube. Use one in an A5 buffer tube and it will have too much travel if not used with a 3/4" spacer. The buffer would also work in other PCC calibers.

I also have a rifle buffer tube setup with one of the Maxim RDS systems. Won't shoot any differently than a carbine buffer tube, but lets me use an A2 stock. Doesn't take anything but a spacer.

I’ve purchased tungsten weights from this company before when I wanted to create my own custom heavy buffers.

https://pur-tungsten.com/product/tungsten-recoil-buffer-weights/

I've designed and made multiple so I'm not sure which one(s) you're talking about.  

Since I mentioned the 9mm, I assume you're asking about it though?  It's the 3rd one down.  

There are others that aren't AR related too.


300 whatchamacallit
9x39
9mm
45

Nope, it is definitely for the A5:

https://www.vltor.com/shop/ar/buffer-components/sp-pcc-a5-pcc-spring-and-buffer-kit/

Sorry. Double tap

The A5 buffers are all 4", which give a 9mm bolt the correct rearward travel in a carbine tube, not an A5 tube. Using an A5 buffer in an A5 tube provides the correct bolt travel for an AR15 bolt, but not the 3/4" shorter 9mm bolt.  

For a 9mm bolt in an A5 tube, an A5 buffer would need to be 3/4" longer than it already is, or have a 3/4" spacer added to the back of the spring.  Without filling the extra space, the user is risking breaking bolt catches and getting cartridges jammed in the lower's trigger pocket just like Colt discovered when using a carbine buffer in a carbine tube with 9mm bolt. Colt decided to add an aluminum spacer to the back of the spring to make up the space difference.  Today most people use 4" buffers.  

Vltor should know better.

I believe they have marketed these buffers as "PCC" because of their weight.  They're too heavy to cycle a gas-operated bolt.

Pay attention to the information above or proceed at your peril the way you think it works. I guarantee you you'll wish you hadn't done it. I've had the A5 system for many years and know for a fact how it works in a 9mm setup.

It won't matter what length buffer system you use, You will want a spacer when using the standard length buffers for each. IE: rifle buffer in a rifle length buffer tube, A5 buffer in a A5 buffer tube, and carbine buffer in a carbine buffer tube. If you don't use a spacer, then you risk breaking the bolt stop and having other associated issues.

I swapped the spacer from my carbine buffer spring to the rifle buffer spring when I fitted my 9mm upper on an A2 lower. Without the buffer, the bolt goes too far back just like with carbine buffer systems without a spacer or extended buffer.