AR pistol build


July 6, 2014, 10:21 PM
im building a pistol. i have the stripped 'virgin' lower, stripped upper, sig brace, lpg with pistol grip, and phase 5 pbt. i would really like input on upg components, and barrel suggestions. does anyone make a bull barrel (for weight out front)?

thanks in advance

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July 6, 2014, 10:23 PM
oh yeah, its for home defense. and its gonna be in 5.56.

July 7, 2014, 05:22 AM
I haven't seen a bull barrel, but it's the AR world, so I'm sure someone makes it. I also haven't needed any extra weight on my 10.5" pistol.

Are you buying it built or building?

Buying complete: BCM, PSA. Both solid, both with good reps. PSA will be a little cheaper, BCM will have better components. Both will work.

Building: that's a deeper question. I yet a YHM slimline handguard, mils per upper I already had, sourced the small stuff (forward assist, delta ring) from midway, and the barrel and BCG from MAS defense. I had no issues with my stuff. But the sky is the limit with AR parts.

I would recommend carbine gas system, and no less then 10" barrel. Also I know you have the receiver extension, but KAK makes one for the sig brace that let's you run a carbine buffer and spring. Helps with reliability.

July 7, 2014, 07:12 AM
I'd go BCM KMR with 11.5" barrel

If you want something functional with pretty much guaranteed quality, but a preassembled upper from BCM or DD.

If you just want a project gun, build it yourself.

You won't save much, if any, money by building it yourself with parts of similar quality.

July 11, 2014, 05:24 AM
For the barrel, I highly suggest at minimum a 10.5" with the carbine gas port. This will ensure the best cycling while still having a short profile. There are plenty of options on barrels out there, so pick a length that suits your needs. You can go shorter of course, but you may run into some cycling issues depending on the config.

Buy a good BCG from Rainier, Spikes, or BCM etc.

Good luck with your build.

July 13, 2014, 11:55 PM
PWS Pistol Buffer Tube

Big Shrek
July 15, 2014, 09:56 AM
Get the best trigger kit you can find.

July 15, 2014, 10:47 AM
I appreciate all the input guys I'm nearly there all that's left is barrel length and the gas system to go with it leaning towards the 10 and a half given the replies I've gotten hopefully some pics to follow thanks again

July 15, 2014, 11:01 AM
Do a bit of searching to find a good deal on a 10.6 or 11.5 inch barrel. The carbine gas system work well with both barrel lengths. Using the Syrac Gen II gas block will allow you to tune the pistol to run reliably and with softer recoil.

The Magpul MOE is a good handguard for the AR pistol as it's simple to install, rugged and very economical. Or the B5 handguard which is slimmer. Free float handguards are nice but cost more and are not necessary. Spend the money towards an Aimpoint instead

July 15, 2014, 01:35 PM
ive got a 7" barrel on mine and have had about a thousand rounds through it with almost no issues... The only issue i did have was the gas block wasnt tightened enough so the gas tube became misaligned. Caused a few jams until i figured it out. Just go with quality components and you wont be disappointed.

July 15, 2014, 05:04 PM
I picked up a 10.5" Melonite-finished barrel from Aero Precision, and I have been extremely pleased. I was able to nab it on sale for under $200. In the last few weeks, I've run about 600-700 rounds through it with no issues.

They make a version without the FSB as well:

So far, it has been flawless on my 10.5" SB-15-equipped pistol build (with the excellent KAK buffer tube that uses the carbine castle nut). With an H2 buffer, it shoots softly and cycles everything from cheap Russian steel-cased .223 to M193 and M855 to heavier match ammo. It is also proving to be just as accurate as my 16" carbine.

I can also say that the Melonite/blackening finish (Aero Precision call it QPQ) is TOUGH, and it resisted my best efforts to mar the barrel when hammering on the FSB and installing the barrel.

Much has been made of the benefits of an 11.5" versus a 10.5" barrel, but I have yet to see them in practice. As stated, this rifle has performed flawlessly, and 10.5" barrels have served well on the Mk18 CQBRs for years now.


July 16, 2014, 08:21 PM
I use Free-float handguards because they are easier to install and add a bit more accuracy depending on your setup. They're not necessarily expensive, depending on where you buy. You can buy them for under $100 at many places including ebay.

Here's another good vendor of AR15 parts. They have freefloat handguards in varying lengths with free shipping:

If you're on a budget, they have a 7.5" pistol barrel for $125shipped.

Here is another Vendor of AR15 parts (SOTA) that has a 8" pistol barrel for $90.

I built a 10.5" AR pistol with a carbine gas system with the SB15 in FDE. The 10" handguard gives it the same sight radius as a midlength rifle although it is a much shorter AR. (

For camparison, here it is with a 16" AR before I installed the SigBrace. (

July 17, 2014, 10:06 AM
BCM 11.5" and a DD 10.5" barrel

Buffer tube:

barreled upper:

H2 buffer(BCM)
Bolt carrier assembley(BCM)
LPK(assorted Colt,LWS)
Charging handle(BCM GF small)
Springs: either ISMI or Wolff

July 17, 2014, 12:05 PM
I use Free-float handguards because they are easier to install and add a bit more accuracy depending on your setup.

I agree, will usually let you get a longer sight radius with your BUIS too.

You probably don't want to go below 10.5" with 5.56 as it'll be hard to find a suppressor rated for it down the road.

Justice06rr's photo with the SB-15 is pretty much my opinion of the sweat spot for such.

July 18, 2014, 07:01 AM
I just got finished putting one together. My goal was a budget friendly AR build. The parts used were a Anderson stripped lower, PSA MOE lower parts kit, and a Androcorp AR 10.5 upper. Like stated above, I would not go below a 10.5 barrel but if you want to go shorter that is your choice. There are many out there to choose from.

These were just a few that I looked at. The only reason I went with the Andro upper was the cost. I was able to purchase the railed model 10.5 complete with BCG and handle for $450 shipped.

Good luck with your build and have fun.

July 21, 2014, 10:20 PM
Buy a 10.3" DD MK18 upper and call it good.

100 yards, Iron sights, first trip to the range. (I can barely see the target at 100 yards using irons.) Shots on the right are me walking the irons into the black.

Zero malf's of any kind in several range trips since this target was shot.

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