First AR pistol "build" tips and ideas

[Gtscotty]

I know the word "pistol" is in the title, but I think it's safe to say the rifle forum is the best place for this discussion

Yesterday I saw a PSA deal of the day, SBA3 brace, Moe lower build kit and EPT trigger for $149. I couldn't pass the package up for the price, so now it's on the way, and I'm trying to figure how I'm going to use it.

Most of my shooting is centered around hunting and longer range rifle (plate shooting, matches every now and then). This pistol AR will be a range toy, so I'm not planning to spend too awful much dough (think PSA nitride uppers on sale) or loading time (needs to eat cheap fodder from my progressive). I'll probably wind up running it suppressed most of the time, plinking inside of 100yds and maybe out to ~400yds depending on cartridge.


The main options I'm interested in, with the Pros and Cons I see are:

5.56 -> 10.5" - 11.5"
PROS:
Cheap - already have stripped lower, just have to buy upper/bcg

Fairly cheap ammo (already set up to load in bulk)

Would be a good use for all the mixed headstamp cases I don't want to feed to my precision AR.

Not a new chambering to load for

Can use a suppressor I already own

Could build an XM177 clone (my favorite machine gun)

CONS:
No subsonic option.

Already have 5.56 ARs

Blasty without a suppressor

300 BLK -> 8.5" - 10.5"
PROS:
Cheap - already have stripped lower, just have to buy upper/bcg

Good subsonic options

Can use a suppressor I already own

CONS:
Supersonic performance is uninspiring

New chambering to load for

Subsonic ammo is relatively expensive to load (heavy jacketed .30 cal bullets are pricey)

Blasty without suppressor

9mm/.40 -> ~8.5"
PROS:
Cheapest ammo - already load in bulk, easiest to load

I don't currently have a PCC, but have been interested for a while

Interoperability with existing collection of Glock mags

CONS:
Pricier to build - have to buy a Glock lower, pistol bcg and an upper.

Don't have a pistol suppressor yet (it's on my list thought)

Shortest range option


Tedious lists aside, I'm interested in hearing what direction other folks have gone with their AR pistol builds. What do you like? What do you not like? What would you recommend?

 

[Varminterror]

As much a fan of the AR platform I am, I just don’t love AR9 PCC’s. For all they are, they aren’t what I really want in a PCC, and certainly not really what I want for a field pistol/SBR. Some guys love them, and it certainly is nice buying big blocks of 9mm ammo for cheap blasting, but I prefer either MP5 clones or more slimline PCC’s. All that said, I don’t love most of the PCC’s in the market - the Ruger PC is as close as I get to joy, but I don’t care for the takedown feature. By the time I built my “AR9,” I could have bought a couple Beretta’s with money to spare towards a keltec. My discontent with most PCC’s (owning a couple dozen over the last 20yrs) stems from the fact they’re as big as a rifle could be, but not as capable.

Personally, the 300blk has never impressed me too greatly either. In a subsonic pistol, you’re not talking about a very capable pistol/SBR either. It’s more capable as a super-sonic option, and the suppressors still knock plenty of decibels off of it to be hearing friendly. My pistols/SBR’s are in .458socom, 5.56, and 6.8. I have pistol barrels for 6.5G and .300blk, but I just haven’t found joy in the 300blk, so I don’t shoot it. It really depends what you want to do - a 150-200grn 300blk is a better choice for 75yrd whitetails than a 50grn 5.56 from a 10.5” barrel, but that’s about the only practical differential where I favor the 300 - and I’d rather have a 6.5 or 6.8 for said use, every day and twice on Sunday.

With 400yrd plinking on the table, 6.5G, 6.8 SPC, and 5.56/223 are the only options I would consider. Doing so with a 9mm or 300blk - especially subsonics - just isn’t very practical, and in my experience, isn’t very enjoyable. For range shooting, I don’t find much difference between a 16” carbine and a 10.5”SBR our to 600.

If I was only going to have ONE upper for hunting and plinking out to 400yrds, it would be a 6.5 or 6.8. If I were only wanting to plink, no game, it would be a 5.56/223.

 

[MistWolf]

Based on my personal experience running a couple of shorties-
- I prefer the 5.56. Cheaper than the 300 BLK, low recoil impulse, flatter trajectory than anything else and easy to tune. I like the 300 BLK and plan to get a factory Colt 9mm SBR, but I like the 5.56 better.

- For a 5.56, an 11.5" barrel gives better downrange performance than a 10.5". I regularly shoot out to 300 yards and more and the 11.5" barrel shoots noticeably flatter and hits harder at the longer distances. A lot of shooters like the 12.5" even better, but I feel that if I were to go 12.5", I might as well go 14.5".

- My first shorty was unsuppressed. Yes, there was a lot of blast but it was fun for me to shoot. Not so fun for my fellow shooters sharing the range with me. Now, my shorties are suppressed and I have no need, or desire, to shoot them without their mufflers.

- Carbine weight buffers suck. They're too light. Use either an H or H2 buffer. Or, use an A5 type RE and an A5H2 buffer with a Sprinco green spring or Colt rifle spring.
- If you want to learn how to tune an AR, build an upper with an SLR adjustable gas block. The experience and knowledge gained form experimenting is invaluable.

- The SBA3 is my favorite arm brace. It can be used on either a standard carbine RE or an A5 RE and greatly simplifies things. It's adjustability is a distinct advantage. Downside is the soft portion is a little too soft.

- Shoot your shorty with regular handguards before spending money on a free float tube. After years of shooting with regular handguards, I have found no need for a free float tube. My favorite handguard is the MagPul Slimline.

- Metal handguards get uncomfortably hot quick! Another reason I like the MagPul Slimline handguards is they do a good job keeping the heat away from your hands.

- Do not use a muzzle brake or compensator unless you want to make enemies at the range. Until you get your suppressor, use either an A2 birdcage, or better still, use a linear comp. Linear comps project the blast forward and downrange. The smallest and lightest of the linear comps is the BRT Covert Comp. A good friend of mine is using one on his shorty and told me it really makes a difference.

- What ever BCG you get, be sure to use a Colt extractor spring. I've tried others, but so far, none have lasted longer or worked better. Reliable extraction is critical with an AR and the shorter the barrel, the more critical extraction becomes.

- The Aimpoint Micro is your friend. The T2 is worth every penny. The best economy brand RDS is the Primary Arms Micro Advanced with rotary dial. However, compare the cost of the PA and mount to an Aimpoint Pro before deciding.

- The Leupold VX-R 1.25-4x30 Patrol is an excellent LPV for the money. It's not a true 1x (few optics are) but still low enough to let the shooter get on target fast at CQB distances. It comes with an illuminated reticle with hold overs. The scope is very light for it's class and optics are clear. Shop around for a good deal. I got mine with a free Leupold AR scope mount.

- I got a 45 degree selector switch from Joe Bobs. It's become my favorite.

- The easiest way to get a solid, reliable AR pistol would be to get the Colt lower (legal to make a pistol with) from Brownell's (on sale for $299. Less, if you can find a discount code), then find a Colt 6933 upper on Gun Broker or G&R Tactical or other supplier. Unsuppressed, it will be gassed just right. It will be a bit over gassed suppressed but that can be taken care of with either a BRT micro port or a BRT gas tube.

The shorties are easily among my favorite ARs to shoot. The kids love'm too, their favorite has the binary trigger (go figure). You'll enjoy yours.

 

[Dr.Rob]

Pistol build: PSA is selling complete Glock and Colt specific pistol lowers for under 200 bucks. Stripper lowers can be had around 100 on sale.

Con: is the lowers are not convertible to 556 or other standard magazine.

Con: pcc AR's can be finicky builds. Bolts are typically expensive.

XM build: you can get a proper barrel 11.5 in a 1/9 from Tony's customs. They also sell the proper looking (not a silencer) moderator. I did a pinned and welded version for my XM that is still 16 inches overall. If you build it as a pistol you don't have to weld the device in place and can swap it out with a silencer at a later date.

I am running my XM clone (built on a complete Colt lower) in a match at the end of the month. I'll let you know how it goes.

 

[Skylerbone]

Having recently asked a few pistol related questions as well gave me a bit of direction and frankly I’m still a bit shocked I didn’t act sooner.

Knowing that a pistol build can be reconfigured as a rifle and back at any time made the SBA3 an easy focus because, so far as I can find it is the only brace that uses a carbine receiver extension. After staking a castle nut I really don’t want to be pulling off a pistol extension and swapping it when I get the hankering. The bigger upside for me is that planning more than a half-dozen builds in the next year or two means buying a single pistol upper to attach will preserve my ability (more correctly my children’s ability) to configure their builds as they choose. Each lower can be photographed with the upper and having a brace will allow them to “try” before they buy.

I settled on 5.56 with a 7” barrel. While a 10ish inch might have been more practical and pleasant to shoot, I reasoned that if I’m going shorter it may as well be markedly so.

With holiday sales in full swing I began throwing parts in carts to add up the damage when I came to my senses on this one (again, because I don’t plan to shoot it much-but I might). Instead of a $500 wonder build and buying tools now, I settled for a completed upper, less BCG and CH for $315 st OpticsPlanet. Aero, MLOK, 4150 QPQ coating. The lower is waiting on an ERGO grip and a trigger guard but hopefully all parts will arrive this week. That’s my reasoning anyway. A sub-compact upper with a familiar round that I also load for which will preserve flexibility in all future builds.

 

[Hokie_PhD]

Knowing that a pistol build can be reconfigured as a rifle and back at any time

Not to hijack the thread but can someone conform or blow this apart.

I thought once you made a lower a pistol it was suppose to be just that. Or am I mistaking this with an SBR? (SBRs are regulated so I can see why they’re not able to be switched around and back and forth)

I’m asking one to get my understanding on track and two for anyone else who reads this thread.

 

[JeeperCreeper]

I'd skip the 9mm build with that lower.

I have both 300blk and 5.56 pistols. The 300blk is pretty fun, but if it's a range toy, 100% go 5.56.

 

[Varminterror]

Not to hijack the thread but can someone conform or blow this apart.

I thought once you made a lower a pistol it was suppose to be just that. Or am I mistaking this with an SBR? (SBRs are regulated so I can see why they’re not able to be switched around and back and forth)

I’m asking one to get my understanding on track and two for anyone else who reads this thread.

The poster was correct: An AR built first as a pistol can become a rifle, and back again, at will. The same is true for any pistol - add a 16”+ barrel and buttstock, and it’s a rifle, and can come back again. It simply cannot be assembled as an SBR, and the parts to constructively possess ONLY an NFA configuration cannot be possessed.

Technically, an AR built as a pistol first, then SBR’d can be made into any of the 3, at will.

An AR built as a rifle first can only be a rifle forever more, unless you involve the NFA Branch. It must be filed and stamped either as an SBR to become an SBR, or a Weapon Made From a Rifle to create a pistol.

 

[Hokie_PhD]

Varminterror thanks for the clarification. I figured I might be mistaken. Hence wanting to make sure someone who was sure clearified as you did.

 

[Gtscotty]

The posts recommending going with 5.56 kind of echo what I was already thinking. I'm already set up to pump out decent 5.56 on my progressive, and have a good idea of what usually works.

With 400yrd plinking on the table, 6.5G, 6.8 SPC, and 5.56/223 are the only options I would consider. Doing so with a 9mm or 300blk - especially subsonics - just isn’t very practical, and in my experience, isn’t very enjoyable. For range shooting, I don’t find much difference between a 16” carbine and a 10.5”SBR our to 600.

If I was only going to have ONE upper for hunting and plinking out to 400yrds, it would be a 6.5 or 6.8. If I were only wanting to plink, no game, it would be a 5.56/223.

If short range whitetails or hogs were on the menu, I'd absolutely be looking at ~12" 6.8s or 6.5s. I used an 18" 6.8 for part of a season and was quite pleased with how well it worked on deer. The animals and areas I hunt now are not so conducive to stumpy AR hunting, the only thing this rig might get used on is coyotes, but even then I'd probably default to my 18" SPR.

I do find the idea of a 12" 6.5G kind of fascinating for a CQB to, say 600 yd option, but I'd have to pick up reloading another round.... Might be worth it.

- For a 5.56, an 11.5" barrel gives better downrange performance than a 10.5". I regularly shoot out to 300 yards and more and the 11.5" barrel shoots noticeably flatter and hits harder at the longer distances. A lot of shooters like the 12.5" even better, but I feel that if I were to go 12.5", I might as well go 14.5".

I like the idea of a 11.5" barrel, I just see a lot more 10.5" uppers for sale. I have put together uppers and have the tools, I was kind of looking for a cheap already assembled upper though, in my experience once I start picking up separate parts to build an upper, the price seems to increase fairly quickly.

Upper wise, I'm thinking something along these lines:

https://palmettostatearmory.com/psa...upper-with-bcg-charging-handle-516445367.html

I'll either use irons or something along the lines of a primary arms, or Sig Romeo 5 red dot. I've had one of the older primary arms rds on a 16" upper for while and it's worked fine.

I have a tunable gas block on my 18" and was able to set it up so that it runs well with a bare muzzle, but still isn't too gassy suppressed (which it is pretty much all the time now). I wonder if an upper like the one above with a standard FSB would be really gassy or have a lot of port pop with my .30 cal can. Basically, should I count on having to run a tuneable or adjustable gas block on a stumpy 5.56?

- Do not use a muzzle brake or compensator unless you want to make enemies at the range. Until you get your suppressor, use either an A2 birdcage, or better still, use a linear comp. Linear comps project the blast forward and downrange. The smallest and lightest of the linear comps is the BRT Covert Comp. A good friend of mine is using one on his shorty and told me it really makes a difference.

I already have a few different cans I could use, but the one I'm planning on using is a Saker 762. It doesn't get much use now that I have my Sovereign Ti can, a shorty AR would be the perfect host to get it back into action. Muzzle device for a 5.56 or 300 will be an ASR flash hider.

XM build: you can get a proper barrel 11.5 in a 1/9 from Tony's customs. They also sell the proper looking (not a silencer) moderator. I did a pinned and welded version for my XM that is still 16 inches overall. If you build it as a pistol you don't have to weld the device in place and can swap it out with a silencer at a later date.

I guess I should have specified a bit better, I wouldn't really do an exact XM177 copy with this build, just something in the same spirit, 10.5"-11.5", very Lightweight, iron sighted or small rds.

 

[Glockula]

I understand the love for a 5.56 here. I really do. But when I went through this 300 blk seemed the logical choice. If 9mm is in play the ballistics are much better than that. Plus 300 blk burns all of its powder in short barrels and isn't as noisy. I have not been a fan of short barreled 5.56 rifles because of their report. As I get older and my hearing gets worse I can see the value in a quiet rifle.

The ballistics of a 300 blk put it between a .357 magnum and a 7.62 x 39. I already hand load a lot of .30 cal calibers and she can be a garbage disposal for .30 cal bullets. Mine is very accurate with supers in the 110 ro 125 range. Subs fall off dramatically accuracy wise past 70 yards. All in all a 300 blk makes a good AR pistol

 

[Skylerbone]

As I get older and my hearing gets worse I can see the value in a quiet rifle.

A reasonable aid at a reasonable price can help alleviate the problem somewhat.



They do come in different lengths but I was considering the idea of a 4” on a 10 1/2” barrel when it struck me odd I was about to be awful close to rifle length again. Now 7 1/2” plus 5” seems more practical and mine too is meant solely for range time at present.

 

[MistWolf]

I like the idea of a 11.5" barrel, I just see a lot more 10.5" uppers for sale.

After spending a lot of trigger time behind both, I found the difference the extra inch made was noticeable. It's worth it to keep searching for an 11.5" upper.

I have a tunable gas block on my 18" and was able to set it up so that it runs well with a bare muzzle, but still isn't too gassy suppressed (which it is pretty much all the time now). I wonder if an upper like the one above with a standard FSB would be really gassy or have a lot of port pop with my .30 cal can. Basically, should I count on having to run a tuneable or adjustable gas block on a stumpy 5.56?

If the gas port is sized right, no adjustable gas block is needed. In fact, if the gas port is the right size, an adjustable gas block is a waste of money. But, getting the gas drive right on a shorty is critical.

I suggest you go experiment with your 18" upper. Shoot it in it's current state of tune, paying attention to how sharp the recoil feels. Then, Now, put a single round in your magazine and load the rifle and shoot it. Keep closing of the gas until the rifle ejects, but does not lock back. Then, open your gas block one click and test to make sure the rifle ejects and locks back. Run 10 or 20 rounds through it, noting how the recoil feels. You'll notice it feels softer (unless you're running a carbine weight buffer. If you're running a carbine weight buffer, get replace it with an H or H2 buffer). That's why my shorties are tuned for optimal function with a suppressor. It won't function without the suppressor, but I never shoot it unsuppressed anymore.

You can use an adjustable gas block on your shorty, but also shop for an 11.5" barrel ported for suppressor use. I believe Sionics is offering one. Or, you can adjust gas flow using a micro port from Black River Tactical or one of their special gas tubes. If you do get an adjustable gas port, get the SLR. They work and customer service is outstanding.

I already have a few different cans I could use, but the one I'm planning on using is a Saker 762. It doesn't get much use now that I have my Sovereign Ti can, a shorty AR would be the perfect host to get it back into action. Muzzle device for a 5.56 or 300 will be an ASR flash hider.

A buddy uses the Saker and likes it a lot. I'm very happy with a direct thread Omega. The setup keeps weight and length down.

View attachment 802194

 

[WestKentucky]

Xm clone yes, 5.56 no. Mine is ridiculously loud and although it’s fun, the novelty wore off quickly.

 

[Styx]

I know the word "pistol" is in the title, but I think it's safe to say the rifle forum is the best place for this discussion

Yesterday I saw a PSA deal of the day, SBA3 brace, Moe lower build kit and EPT trigger for $149. I couldn't pass the package up for the price, so now it's on the way, and I'm trying to figure how I'm going to use it.

Most of my shooting is centered around hunting and longer range rifle (plate shooting, matches every now and then). This pistol AR will be a range toy, so I'm not planning to spend too awful much dough (think PSA nitride uppers on sale) or loading time (needs to eat cheap fodder from my progressive). I'll probably wind up running it suppressed most of the time, plinking inside of 100yds and maybe out to ~400yds depending on cartridge.


The main options I'm interested in, with the Pros and Cons I see are:

5.56 -> 10.5" - 11.5"
PROS:
Cheap - already have stripped lower, just have to buy upper/bcg

Fairly cheap ammo (already set up to load in bulk)

Would be a good use for all the mixed headstamp cases I don't want to feed to my precision AR.

Not a new chambering to load for

Can use a suppressor I already own

Could build an XM177 clone (my favorite machine gun)

CONS:
No subsonic option.

Already have 5.56 ARs

Blasty without a suppressor

300 BLK -> 8.5" - 10.5"
PROS:
Cheap - already have stripped lower, just have to buy upper/bcg

Good subsonic options

Can use a suppressor I already own

CONS:
Supersonic performance is uninspiring

New chambering to load for

Subsonic ammo is relatively expensive to load (heavy jacketed .30 cal bullets are pricey)

Blasty without suppressor

9mm/.40 -> ~8.5"
PROS:
Cheapest ammo - already load in bulk, easiest to load

I don't currently have a PCC, but have been interested for a while

Interoperability with existing collection of Glock mags

CONS:
Pricier to build - have to buy a Glock lower, pistol bcg and an upper.

Don't have a pistol suppressor yet (it's on my list thought)

Shortest range option


Tedious lists aside, I'm interested in hearing what direction other folks have gone with their AR pistol builds. What do you like? What do you not like? What would you recommend?

Wait until PSA has deal on on 7.63x39 uppers. The ballistics of 300blk out of short barrel for the price of 2.23/5.56

 

[MistWolf]

Wait until PSA has deal on on 7.63x39 uppers. The ballistics of 300blk out of short barrel for the price of 2.23/5.56

If you do, make sure to get the lower that uses AK mags

 

[Styx]

If you do, make sure to get the lower that uses AK mags

You can use regular 223/556 lowers. You just have to buy mags that'll fit. They aren't that expensive. Most use C-Products steel mags.. Runs under $20.

 

[Dr.Rob]

I guess I should have specified a bit better, I wouldn't really do an exact XM177 copy with this build, just something in the same spirit, 10.5"-11.5", very Lightweight, iron sighted or small rds.

https://www.tonyscustomsllc.com/product-category/parts-components/barrels/11-5-inch-barrels/

https://www.tonyscustomsllc.com/product/ar-15-xm-177-style-flash-hider/

If you choose this option make sure you call and get the proper hand guard ring.

 

[MistWolf]

You can use regular 223/556 lowers. You just have to buy mags that'll fit. They aren't that expensive. Most use C-Products steel mags.. Runs under $20.

The case taper of the 7.62x39 case requires a magazine with a constant curve. 223/5.56 lowers need mags with a straight section in order to fit in the magwell which causes feed problems.

 

[entropy]

Not to hijack the thread but can someone conform or blow this apart.

I thought once you made a lower a pistol it was suppose to be just that. Or am I mistaking this with an SBR? (SBRs are regulated so I can see why they’re not able to be switched around and back and forth)

I’m asking one to get my understanding on track and two for anyone else who reads this thread.

A pistol can be reconfigured to a rifle and back, doing it the other way (rifle to pistol and back to rifle) will get you ten.

Gtscotty, put a linear compensator on it if you don't put a can on it; well worth it.

 

[IndianaBoy]

I was in a similar situation as you a while back.


I settled on an 11.5 223 Wylde and I shoot is suppressed 99% of the time.

My rationale: 11.5 was the sweet spot for retaining decent ballistic performance but still being short enough to be much handier with the can on the end of the barrel. I regularly shoot it out to 250 yards with no difficulty at all with a red dot.

Why not 300 blackout? Because of the poor sectional density of the supersonice 300blk ammunition. 70 grain Barnes TSX bullets out of my 11.5 offer, IMHO, better performance than a 125gr 30 cal bullet.

If I wanted a quiet gun, 9mm offers much cheaper ammunition with reasonably approximate ballistic performance of the heavy subsonic 300blk ammo. Not quite on par, but not enough difference to make the additional cost worthwhile to add another caliber.

11.5 223 suppresses reasonably well. Not great. But ok.


Do I wish I had giggle inducing quiet guns? Sometimes, yeah, but I could eventually accomplish that with a 22lr. Other than a range toy, there isn't much you can do with a gun shooting subsonic ammo. If it is a range toy, for me, 22lr is good enough.


I might eventually do a 300blk or 9mm AR build. But it isn't a priority.


My 11.5 pulls bedside duty with the silencer in place and a white light on the handguard. It shoots very well, but it did need an H3 buffer. The gas port is sized properly to be shot unsuppressed, which makes it overgassed with the can in place. I also added an adj gas block.

 

[Styx]

The case taper of the 7.62x39 case requires a magazine with a constant taper. 223/5.56 lowers need mags with a straight section in order to fit in the magwell which causes feed problems.

They make magazines that feed reliably for the regular 223/556 lower. They're made by a company called C-Products.

https://www.primaryarms.com/c-products-30-round-ar-15-magazine-762x39-3062041205cpd

They can be found by multiple retailers from $15-$22 or so dollars each. There are multiple YouTube vids, forum threads, and positive reviews arcoss the inet on them. They're g2g.

 

[adcoch1]

I really like 300 blk in a short barreled pistol, 5.56 is very blasty under a 10.5" barrel but fun to shoot. I have a current build in 458 socom with an 8" barrel that I haven't shot yet but should be a lot of fun. I don't buy in to a lot of the hype on 300 blk, but it is very pleasant to shoot sub or supersonic, and easy to load for. I just cant get myself to build a 9mm ar when the blk is available and I have three short uppers in it. A 45 pistol upper would be fun, but I can load 300 blk for the same price and get better ballistics and use better (or at least cheaper) mags. For a pistol I really like the modern 30 carbine the blackout has turned out to be. That said I may build a 6.5grendel pistol to go with my new rifle upper. Gotta get some ammo first though and see how I like the rifle.

 

[Chuck R.]

I'm going through the same decision right now, lucked into a Maxim Defense PDW brace on sale and an Aero Lower at our post skeet club.

Waiting on a Larue MBT and the lower's complete. Trying to decide on caliber and leaning towards a 10.5" 300BLK with a linear comp. I've got no plans for a suppressor. I've already got a Colt AR6951 in 9mm, so the PCC base is covered although I think a 9mm PCC pistol with a maxim brace would be pretty nifty and I think my IDPA club would let me run it in matches as I run the Colt occasionally now.

 

[Armored farmer]

I echo the 5.56 pistol.
It is my favorite AR. It fills a niche, and scratches an itch for me.
With a .22lr conversion kit, you can be even more versatile.