View Full Version : AR Pistol Build Questions

09-21-2012, 1:36 PM
Hey guys, I'm about to complete my first 80% lower and plan on making an AR Pistol. I own a full size AR rifle, but have never built one before.

My first question is what pistol buffer tube do you guys recommend? I would like the shortest possible or if there is another you like would love to hear why.

I have seen alot of options for pistol uppers like the AR57, and I am not sure if all are even CA legal.

So second question is there a thread you can point me to where I can see the laws regarding AR pistols? regarding length features clip size ect? I have searched to no avail.

Last question what would you guys recommend as a complete upper, to slap on my pistol lower. I would like something in the 7"-10.5" range. Is 7" too short? I'm open to suggestions on caliber if you like something non-standard.

Thanks for your input.

09-21-2012, 5:43 PM
Look ^^up^^

The flowcharts and OLL assembly guide section has the legal answers.

Shortest buffer assembly is the GSE but I don't like it, it's really not a buffer, just a buffer spring and they lighten the bolt carrier at the same time.

I prefer the Spikes Tactical pistol buffer tube or the PWS enhanced pistol buffer tube. Those both use standard carbine style buffers. The Spikes uses a standard carbine end plate and castle nut. The PWS mounts with a unique system but has a couple QD sling swivel sockets and is very clean. The PWS also has the lower edge extended which prevents carrier tilt (good if you have a gas piston system).

For the upper, 10.5" (or so) with carbine gas in 5.56 is about as reliable as you can get for a pistol.

Shorter barrels like 7.5" with pistol gas systems are more difficult to get right (but not too bad).

Blowback ARs like 9mm will run very well regardless of barrel length.

7.62*39 is good if you like cheap ammo, .300 AAC Blackout is good if you like reloading and want something heavier hitting, 6.8 SPC works well in short barrels but it is expensive, 6.5 Grendle doesn't make a lot of sense for a pistol, .458 SOCOM and .50 Beowulf are good if you like recoil.

09-21-2012, 5:47 PM
AR uses Clips?! Lol... Jk.

When I built my AR pistol, I thought I wanted a short buffer...after building it I'm glad I got the longer one...better use for it IMO

09-21-2012, 5:58 PM
Oh, as for the AR57 upper, I like the idea but the CA "assault weapon" ban kind of ruins it. You have to run a fixed 10 round magazine and the solutions out there kind of suck.

In the free world with detachable 50 round magazines it's a really neat idea and cheaper than a PS90 but in California, not yet.

09-21-2012, 10:57 PM
Thanks for the info man. I know about the rifle flowchart does that apply to an AR pistol?

When you say a 7inch is harder to get right. You mean if i built myself or even if i buy a complete upper?

09-21-2012, 11:30 PM
Why not try the handgun flowchart...

As for the 7", yes.

09-22-2012, 3:10 AM
Ok that's what I needed to know, so it legally is considered a handgun then thanks.

And yes to what lol? hard to build? or they dont even work good when prebuilt?

Do they not cycle or too hard to shoot?

Thanks you seem to know alot just trying to understand.

Also are there any bufferless options for an AR15 pistol build?

09-22-2012, 3:37 AM
I have an 80% lower, Young Manufacturing 7.5" upper.
Overall length is a touch under 18 1/2".
Got the upper from http://www.architects15.com/
Highly recommend them. Great service and price.
400-500 rounds and not a single problem*

*I'm a lefty. Was out in NV and dropped in a 30 rounder for a spray and pray mag dump. I was using some steel cased ammo. "Brass" came out so hot one of them stuck to the crook of by right arm and gave me a nasty burn. I'm pretty sure I could injure myself in a room full of feathers.:facepalm:

09-22-2012, 10:59 AM
Yes to both.

Pre-built and tested has a better chance but the carbine gas system was designed for "commando" style 10-11.5" barrels so it's arguably easier to set up than a 14.5" with carbine gas (the M4 rifle...).

Pistol gas was an afterthought, I'm aware of no standards so a properly tuned pistol is a matter of actually tuning it instead of just popping on a commando upper and going shooting.

09-22-2012, 11:05 AM
You can do a .22lr AR pistol without a buffer.

Paraordinance makes a "bufferless" setup but I'm not sure how available parts are.

But the most important thing is that a standard pistol buffer tube gives you something to cheek and the buffer system is on the AR for a reason, it slows down the bolt and buffers vibration so that the bolt does not bounce when it closes on the chamber. That bounce can cause out of battery firing or partial lug bearing which is bad. It also changes the balance quite a bit and ARs are still barrel heavy with a buffer tube.

09-23-2012, 5:09 AM
Ok thanks again.

Im looking at a phase 5 tactical pistol buffer tube are they any good or should i stick with spikes? The pws was outa stock.

09-23-2012, 10:21 AM
I have no experience with them but evidently they do a lot of pistol stuff.

The good thing about Spikes is that you can use standard end plates and a lot of carbine stock accessories while some of the others like the Rock River tube require a modified end plate.

Maybe look at the ACE pistol buffer tube setup too.