Educate me on AR pistols

[MGW]

I’m in the market for a new rifle. I own one AR and one day it’ll go to my now teenage son. My experience is mostly with 14.5” and longer carbines and rifles. I don’t have a practical need for a rifle. I won’t hunt with it and it won’t be a house gun. A 11” lightweight pistol sounds really versatile on paper. Something that is a jack of all trades but master of none. Easy to travel with. Easy to use in and around vehicles and buildings. I guess I see it as the Glock 19 of the AR world. But honestly I don’t know what I don’t know.

As an example this is a set up that’s interesting to me.

https://www.instagram.com/p/B2q9QlJlvfE/?igshid=1bj6xofed8av

So educate me. What do I need to know about an AR pistol before I plunk the money down on one?

[Grey]

I’m in the market for a new rifle. I own one AR and one day it’ll go to my now teenage son. My experience is mostly with 14.5” and longer carbines and rifles. I don’t have a practical need for a rifle. I won’t hunt with it and it won’t be a house gun. A 11” lightweight pistol sounds really versatile on paper. Something that is a jack of all trades but master of none. Easy to travel with. Easy to use in and around vehicles and buildings. I guess I see it as the Glock 19 of the AR world. But honestly I don’t know what I don’t know.

As an example this is a set up that’s interesting to me.

https://www.instagram.com/p/B2q9QlJlvfE/?igshid=1bj6xofed8av

So educate me. What do I need to know about an AR pistol before I plunk the money down on one?

What do you want this rifle to do? Is this just for fun or are you actually planning on driving around with it in a vehicle?

[Bigghoss]

A 10.5" barrel is generally considered the bare minimum for .223/5.56. any less and the guns tend to to be less reliable and the bullet doesn't have the velocity to do what it's supposed to do. Most will say 12.5" is better for both aspects. If you want to go shorter you want to look towards a .300blk.

[SecondsCount]

A 10.5" barrel is generally considered the bare minimum for .223/5.56. any less and the guns tend to to be less reliable and the bullet doesn't have the velocity to do what it's supposed to do. Most will say 12.5" is better for both aspects. If you want to go shorter you want to look towards a .300blk.

I agree, having shot both a 10.5 and a 12", the latter is preferred. Suppressed may be a different story.

[MGW]

A 10.5" barrel is generally considered the bare minimum for .223/5.56. any less and the guns tend to to be less reliable and the bullet doesn't have the velocity to do what it's supposed to do. Most will say 12.5" is better for both aspects. If you want to go shorter you want to look towards a .300blk.

This is the kind of stuff I need to know. I’m mildly curious about 300BO but sticking with 556 for now seems like a smarter move.


I agree, having shot both a 10.5 and a 12", the latter is preferred. Suppressed may be a different story.

I don’t think I’ll suppress it. But if I did would the extra 1.5” make that big of a difference?

[MGW]

What do you want this rifle to do? Is this just for fun or are you actually planning on driving around with it in a vehicle?

Yes and yes. I plan on shooting it a lot and roaming around with it.

[Grey]

This is the kind of stuff I need to know. I’m mildly curious about 300BO but sticking with 556 for now seems like a smarter move.



I don’t think I’ll suppress it. But if I did would the extra 1.5” make that big of a difference?

300 BO really makes sense if you're going to shoot subs and/or you want the shortest barrel possible. I think you can get down to a 8" and it runs.

If you aren't going to suppress it then definitely go for a 12.5" barrel. If you were making it a dedicated suppressor host I'd still say go 11.5. Yes MK18 (10.5") guns run but there are better options these days.

[Casual Friday]

I'm a fan of 11.5" guns. My favorite is my BCM upper with the ELW profile barrel, MCMR rail, Colt lower, Aimpoint Pro, Magpul Pro BUIS, Larue MBT flat 2 stage trigger. I've since switched to a scout light with pressure switch since this photo was taken earlier in the summer but you get the idea. I personally won't go under 11.5", under that and things get finicky and the guns are either running good or beating themselves to death.

I consider an 11.5" pistol to be the perfect travel gun, especially with the Law folder which I have on another 11.5", it fits nicely in my Vertx bag. This one pictured is the gun I throw in the floorboard of the truck when we take our drives up into the mountains. With a proper gas port and the A5 buffer system, it shoots smooth as buttah.

42963

[Bigghoss]

Garand Thumb did a video not too long ago about AR pistols. That dude shoots a lot and he said he likes 12.5" for unsurpressed and 11.5 for surpressed. The surpressors is going. To give more back pressure so that should help it but my 10.5 pistol runs good so far with an H2 buffer. Mine is a PSA kit though so they probably put a big gas port in the barrel knowing their customers are going to run the cheapest ammo they can find. (Which is part of the reason I bought it.)

I was thinking about it the other day. If you have a 12.5" barrel with, say, an A2 flash hider you're only about 2.25" shorter than a 14.5" with a permanently attached A2X flash hider. Having done a little (not a lot) of training and practice clearing buildings I think even a couple inches off the barrel is a good thing. But it still makes you pause and think it over. When I get around to building my 12.5" pistol I'm going to spring for a LAW folder.

I've also saw that a few companies are starting to offer 13.7" barrels for the longer muzzle devices designed for attaching surpressors so you can pin and weld and get the barrel up to 16.1".

For braces, the SBA4 is my current fav with the SBA3 being a close second. I found the SBA3 to be a little too short on a standard tube screwed directly into the reciever. The A4 is about an inch longer which is just about right for me. I've only tried those two and the Blade though. The Tailhook looks pretty good but as far as I know you can't use it on a standard carbine tube like the SBA3/4 braces. My only complaint about the SBA4 so far is where they put the sling attachment points.

[Sensei]

If having you AR rifles standardized on the same cartridge is important to you, I say go with an 11.5” barrel in 5.56.

I’d recommend this upper if you like M-Lok: https://www.bravocompanyusa.com/BCM-BFH-11-5-Carbine-Upper-Receiver-MLOK-MCMR-10-p/bcm-urg-11-bfh-mcmr-10.htm

Or, this upper if you have a bunch of Keymod accessories: https://www.bravocompanyusa.com/BCM-BFH-11-5-Carbine-Upper-Receiver-Group-w-BCM-p/bcm-urg-11-bfh-kmr-a-10.htm

On the other hand, if having a super-short barrel is of utmost concern, then 300blk is really the best way to go and still maintain a high degree of parts commonality. 6.8SPC is another ultrashort option with marginally better terminal performance over 300blk, but even less parts commonality with your 5.56. However, there are far fewer very high performing, barrier blind loads in 300blk compared to 5.56. The 110 grain Barnes TAC-TX (black tip) is the best out there in 300blk, and pushed from a 9” barrel at 2150 fps will absolutely ruin someone’s day. I’ve taken the 300blk down to 5.5” in the form of a Sig Rattler and it still pushes the TAC-TX to 1800+ fps on my chrono - that’s 100+ yards of expansion margin assuming a threshold of 1500 fps.

42966

[JRB]

I have found that any 5.56 under 10in is just miserable to shoot, even with earpro. There are many ballstics-by-the-inch style reviews of typical 5.56/.223 performance as barrels get shorter, and there's a marked drop-off in performance starting around 10in.

My personal favorite AR pistol right now is built as follows:
Factory Colt 933 11.5in upper and Colt BCG
Aimpoint Comp M4S on Aimpoint riser, Old school KAC rail system
Aero lower w/BCM LPK and trigger, Umbrella corp pistol grip
Colt H3 buffer, JP enterprises quiet buffer spring
Gearheadworks Tailhook brace & tube
Vickers Sling

It is boringly reliable with every brass cased ammo I've tried, and it's about 95% on steel case garbage, even with mixmaster old GI magazines. It shoots noticeably better and somehow softer with the Hornady Black 75gr SBR load and that's what I tend to keep loaded in it.
It's fast and easy to point and shoot, and I can run everything about that weapon without thinking, and steel gongs anywhere inside of ~250 yards are mine for the taking.

That said, even at 11.5in it's noticeably louder and harsher than my pinned & welded 14.5in. So I think my next pistol build, whenever that happens, will likely be a 12.5in BCM. But I'm torn between that and just setting up the 11.5 with an H5 or similar buffer and a YHM turbo or similar suppressor.

Since you're still in the testing & evaluation phase of this, There's a lot to be said for simply buying a budget gun and seeing how you like it. Ruger's 10.5in AR556 pistol comes out of the box with the SBA3 and can be found easily for $550ish plus transfer costs, though that's 10.5in.
Alternatively, PSA has been offering an 11.5in 933-esque upper with BCG for under $250 and that'd make for a cheap build to see how you like the concept without a lot of cash outlay.
For a 'working' gun, I'd recommend sticking to Colt, FN, Sionics, BCM, SOLGW, or another known higher quality manufacturer.

[Bigghoss]

I just remembered this thread that talks in more detail about barrel length for the 5.56 cartridge. I'm sure there's others too.

https://pistol-forum.com/showthread.php?37944-5-56-10-5-quot-barrel-thoughts-for-LE-work

One nice thing about barrels 10.5" and up is that they will typically use a carbine gas system and if you want you can get uppers and barrels with fixed front sight towers and delta rings so you can drop in any carbine handguard. BCM also makes 12.5" uppers that are set up to take midlength handguards with low profile gas blocks and then a fixed front sight tower further out similar to a 16" faux dissapator. It's got me wondering if a MK18 mod 0 clone would look weird with a midlength handguard.

Not sure if you're aware but you can't have a vertical grip on a "pistol". A pistol is under 26", measured WITHOUT the brace installed, so muzzle to end on the buffer tube. You are allowed to have an angled fore grip though. Now if the gun is over 26" without a brace it's not technically a pistol and is just a firearm which means you can have a vertical grip if you want.

[MGW]

I just remembered this thread that talks in more detail about barrel length for the 5.56 cartridge. I'm sure there's others too.

https://pistol-forum.com/showthread.php?37944-5-56-10-5-quot-barrel-thoughts-for-LE-work

One nice thing about barrels 10.5" and up is that they will typically use a carbine gas system and if you want you can get uppers and barrels with fixed front sight towers and delta rings so you can drop in any carbine handguard. BCM also makes 12.5" uppers that are set up to take midlength handguards with low profile gas blocks and then a fixed front sight tower further out similar to a 16" faux dissapator. It's got me wondering if a MK18 mod 0 clone would look weird with a midlength handguard.

Not sure if you're aware but you can't have a vertical grip on a "pistol". A pistol is under 26", measured WITHOUT the brace installed, so muzzle to end on the buffer tube. You are allowed to have an angled fore grip though. Now if the gun is over 26" without a brace it's not technically a pistol and is just a firearm which means you can have a vertical grip if you want.

I forgot about the vertical grip on pistols. Thanks for the reminder. I think an angled fore grip is a must with a short barrel.

Quick NFA question. If I buy a complete short barrel upper with the intent of making it a pistol, do I still have to go through the stamp process? I ask because the BCM upper has NFA in big letters at the top of the page.

I’m really not up on NFA stuff at all.

[MGW]

If having you AR rifles standardized on the same cartridge is important to you, I say go with an 11.5” barrel in 5.56.

I’d recommend this upper if you like M-Lok: https://www.bravocompanyusa.com/BCM-BFH-11-5-Carbine-Upper-Receiver-MLOK-MCMR-10-p/bcm-urg-11-bfh-mcmr-10.htm

Or, this upper if you have a bunch of Keymod accessories: https://www.bravocompanyusa.com/BCM-BFH-11-5-Carbine-Upper-Receiver-Group-w-BCM-p/bcm-urg-11-bfh-kmr-a-10.htm

On the other hand, if having a super-short barrel is of utmost concern, then 300blk is really the best way to go and still maintain a high degree of parts commonality. 6.8SPC is another ultrashort option with marginally better terminal performance over 300blk, but even less parts commonality with your 5.56. However, there are far fewer very high performing, barrier blind loads in 300blk compared to 5.56. The 110 grain Barnes TAC-TX (black tip) is the best out there in 300blk, and pushed from a 9” barrel at 2150 fps will absolutely ruin someone’s day. I’ve taken the 300blk down to 5.5” in the form of a Sig Rattler and it still pushes the TAC-TX to 1800+ fps on my chrono - that’s 100+ yards of expansion margin assuming a threshold of 1500 fps.

42966

300 has a lot of appeal. But from what I’ve seen it ups ammo costs significantly. I’m not set up to reload for 300 so off the shelf will be my only option for awhile. I want to shoot this rifle a lot without going completely broke.

[23JAZ]

I would definitely go with the 11.5. I just built one a few months ago and couldn’t be happier. It’s the perfect configuration IMO. I am going to put a LAW folder on it as soon as I talk myself into spending the money.
42971

[JRB]

I forgot about the vertical grip on pistols. Thanks for the reminder. I think an angled fore grip is a must with a short barrel.

Quick NFA question. If I buy a complete short barrel upper with the intent of making it a pistol, do I still have to go through the stamp process? I ask because the BCM upper has NFA in big letters at the top of the page.

I’m really not up on NFA stuff at all.

No stamp/approval or anything else needed so long as it's a pistol with a brace. Some states require that an AR pistol be marked 'pistol' so be mindful of that, it's cheap CYA when buying a lower as there's many AR lowers available that are marked 'pistol'.

The overall length (OAL) over 26in without the brace installed is another plus for the 11.5in barrel - an 11.5in upper with a carbine/pistol buffer tube will be over 26in OAL and thus can have a forward PG without being an NFA issue. It is technically a 'firearm' at that point as far as the NFA is concerned.

[Casual Friday]

I forgot about the vertical grip on pistols. Thanks for the reminder. I think an angled fore grip is a must with a short barrel.

Quick NFA question. If I buy a complete short barrel upper with the intent of making it a pistol, do I still have to go through the stamp process? I ask because the BCM upper has NFA in big letters at the top of the page.

I’m really not up on NFA stuff at all.

A hand stop like the BCM KAG or Arisaka's hand stop would be a better choice than an AFG if you need it, especially better than Magpul's AFG, good grief that thing is worthless. I much prefer a c clamp grip and find that to be more than sufficient with a properly gassed setup.

Companies like BCM put the NFA disclaimer for legal purposes so no one can say "Well BCM sold it to me" after they get caught with their unregistered SBR. There is no federal requirement for pistols but I'm not certain about each individual state's laws.

[MGW]

Companies like BCM put the NFA disclaimer for legal purposes so no one can say "Well BCM sold it to me" after they get caught with their unregistered SBR. There is no federal requirement for pistols but I'm not certain about each individual state's laws.

Perfect. Thank you.

[Doc_Glock]

300 has a lot of appeal. But from what I’ve seen it ups ammo costs significantly. I’m not set up to reload for 300 so off the shelf will be my only option for awhile. I want to shoot this rifle a lot without going completely broke.

I have 11.5" ELW KMR upper from BCM that is probably my favorite rifle to shoot. Highly recommended.

I also have a 300 BLK upper that is fine, but the ammo cost bugs me to shoot it much.

I have limited rifle experience, but the 11.5" BCM linked above by someone has lived up to the hype being reliable, accurate and a lot of fun to shoot and easy to handle with the shorter barrel.

My question would be which "pistol brace" du jour is recommended? All my lowers are SBR stamped and I think I would like a pistol lower.

[Casual Friday]

I have 11.5" ELW KMR upper from BCM that is probably my favorite rifle to shoot. Highly recommended.

I also have a 300 BLK upper that is fine, but the ammo cost bugs me to shoot it much.

I have limited rifle experience, but the 11.5" BCM linked above by someone has lived up to the hype being reliable, accurate and a lot of fun to shoot and easy to handle with the shorter barrel.

My question would be which "pistol brace" du jour is recommended? All my lowers are SBR stamped and I think I would like a pistol lower.

The SBA3 or SBA4 are probably the top 1 and 2, and for good reason. They're adjustable and comfortable to use.

[Clusterfrack]

Palmetto 7.5” 300 BO melonited, Doublestar Strongarm brace. BCM BCG and charging handle. With an H3 buffer it works great with supersonic loads. I’ll be adding a front BUIS soon.

https://uploads.tapatalk-cdn.com/20190926/0e87cb21a7c77a5590409bd1b3d01d47.jpg

[psalms144.1]

Just in case you haven't heard it enough, we went through quite a few Mk18s that had to go back to Crane for depot maintenance in heavy use. The first one I was issued wouldn't go through a basic load of ammo in a training day without starting to choke. That was with a carbine that was spit shined and lubed heavily before the first round was fired. Based on that experience, I don't like any direct impingement 5.56 with a barrel 10.5 or shorter.

I don't know enough about the BO to make an expert prediction, but if I wanted an uber-portable AR pistol, I'd probably go that route. I've been desperately tempted by some of the 8" 300BOs I've seen...

[Grey]

If I was putting together a pistol right now... BCM 12.5, or a KAC 11.5 SR-16 (if you can find one...).

[jandbj]

If I was putting together a pistol right now... BCM 12.5, or a KAC 11.5 SR-16 (if you can find one...).

Having shot my SBR with 10.5, 11.5, & 12.5” uppers.... the BCM Kino 12.5” is here to stay for me. Handles great, runs smooth and I like the mid length handguard and fixed front sight.

[Bigghoss]

the BCM Kino 12.5” is here to stay for me. Handles great, runs smooth and I like the mid length handguard and fixed front sight.

That's the one I was thinking of, couldn't remember the name. Yeah, I really want to do a pistol with one of those uppers.

[Bigghoss]

My question would be which "pistol brace" du jour is recommended? All my lowers are SBR stamped and I think I would like a pistol lower.

I've only tried the SBA3, SBA4, and the Shockwave Blade. SBA4 is my favorite, the SBA3 doesn't give enough LOP for me on a standard pistol setup. With a LAW folder it would be fine or maybe even an A5 buffer tube. The SBA4 also looks a little more like a carbine stock so aesthetically it's better for my MK18 clone. I have an SBA3 on an AK pistol with a folding hinge and it's perfect for that gun.

[MolonLabe416]

I went with a 300 BO Saint. I swapped the brace for an SBa3 and topped it with an Aimpoint PRO.


https://www.springfield-armory.com/products/saint-ar-15-pistol-300-blk/

[Sensei]

300 has a lot of appeal. But from what I’ve seen it ups ammo costs significantly. I’m not set up to reload for 300 so off the shelf will be my only option for awhile. I want to shoot this rifle a lot without going completely broke.

Then I’d stick with 5.56. Assuming that you will use a PSB, I’d go with 11.5” barrel if you plan to shoot suppressed; 12.5” is also reasonable but probably unnecessary if you want the shortest barrel possible but still very reliable.

This gun is an 11.5” BMC that has been 100% reliable:
42996

This 14.5” KAC is also 100% reliable albeit a whole lot more expensive:
42997

This 10.5” KAC IWS lower with a 10.5” barrel LMT MRP upper (cost me a kidney) is also reliable but shot suppressed 90+% of the time:
42998