Best barrel length for ar pistol

[ChrisBrooklyn]

Hey all. I'm in the process of building an ar pistol and I'm not sure about barrel length. I was thinking 10.5 or 12. But I've read tons of conflicting stuff about problems cycling with certain lengths. Also will my barrel length affect the buffer tube size? Or just a standard pistol buffer for all? Thanks for any expertise.

[bonesurf]

Best barrel length for ar pistol

I got a 7.5" pistol gas. Standard buffer and spring. GTG. Doesn't make it "the best" cause I don't exactly know what you mean by that but it works.
(This is 223/556)



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[John Browning]

8.5in in .300 AAC.

[ChrisBrooklyn]

I'm gonna stick with 5.56 just for continuity between my rifles. I have an m1a for when I need some 30 caliber punch.

[swift]

I have used a 10.5" on my ar15 pistol and it runs great. While I am happy with it, the next barrel will be 12 -12.5". I would do this for two reasons: the added velocity and because the added length should allow the addition of a forward pistol grip (grip pod) without making it an AOW. Note: this is not legal advice. There is an ATF letter that states Franklin Armory's ar15 pistol with a forward grip is not an AOW due to it's length. (Just to be sure of my understanding, I would get this in writing for MY pistol before adding a grip pod.)

Velocity info:

http://counterstrikefox.freeservers.com/

[jcwatchdog]

Hey all. I'm in the process of building an ar pistol and I'm not sure about barrel length. I was thinking 10.5 or 12. But I've read tons of conflicting stuff about problems cycling with certain lengths. Also will my barrel length affect the buffer tube size? Or just a standard pistol buffer for all? Thanks for any expertise.

Buffer tube will be the same, but the buffer itself will change depending on the length. I had a 7.5" spikes tactical, it was fun and loud, but not very comfortable to shoot. I like shouldering the tube, and with 7.5, it makes it more difficult. I recently made one with a 10.3 DD MK18 and it's much nicer. I'd stick with the longer lengths, unless you just want to be an attention whore at the range, then get the 7.5"

[steveOsteezy]

If your looking more comfort when shouldering the I can recommend a CAA stock saddle. It provides a great cheek weld and I had no problem hitting steel plates at 100 yards, I will try 200 next trip.


It mounts tight in the back but I have the front held down with gorilla tape until I get some hardware for it. The ATF approved of mounting this item to a buffer tube, there's a letter floating around ar15.com confirming this.

[Dark Mod]

If your looking more comfort when shouldering the I can recommend a CAA stock saddle. It provides a great cheek weld and I had no problem hitting steel plates at 100 yards, I will try 200 next trip.


It mounts tight in the back but I have the front held down with gorilla tape until I get some hardware for it. The ATF approved of mounting this item to a buffer tube, there's a letter floating around ar15.com confirming this.

Are those cast boolits in the first 2 mags?

[steveOsteezy]

Yes, they are 230 & 155 grain cast from lee molds.

[steveOsteezy]

On the topic of 5.56 from a short barrel, you might want to consider a 12.5" barrel.

5.56 is quite obnoxious out of a 10" barrel from my experience, I can't imagine going any shorter than that. The cartridge isn't very effecient in short barrels so you end up burning tons of powder out of the barrel which creates a loud blast and flash. A cmmg .22 conversion kit is a nice companion in this scenario.

[peter95]

Best would be 12.5" plus. Anything shorter will not reliably bring the projectile up to fragmentation speed.

[SDM44]

I've ran both 7.5" and 10.5" barrels on my AR pistol builds. Put a good. 200-300 rounds of 55gr 5.56 through each of them as well.

With a Wolff extra power recoil spring and heavier buffer, the pistols ran flawless and the casings ejected at the 3:00 position about 2ft away.... perfect IMO. I never tried a stock recoil spring & buffer in my pistols because I've always had the extra parts for them and knew it would run with it.

[Dhena81]

Buy a 11.5 Colt commando barrel from specialized armament.

[Germz]

http://www.calguns.net/calgunforum/showthread.php?t=839619

Quick reference to troubleshoot timing/cycling. This should address any concerns about short barrels not cycling or the like:


Not my picture. This belongs to AR15barrels:

Barrel length means nothing until you bring the gas system length, the cartridge and the bullet weight into the fray as well.
Different buffers allow you to tune a gun to run at it's optimum.
Ammo is also a big factor in which buffer to use.
Anyone that tells you a specific buffer is what you need for a specific barrel does not know what he is talking about as there are no absolutes here...

[Munny$hot]

Best would be 12.5" plus. Anything shorter will not reliably bring the projectile up to fragmentation speed.

If fragmentation is a concern according to Nosler, their Ballistic tips will fragment at any velocity. IIRC a 10" barrel is the minimum M193 or M855 will fragment but at a very short distance. 11.5 made a decent difference and only adds an additional 1.5". Going longer in lengths will increase your range with military ammo.