- Jul 29, 2014
- 49,982
I like being able to see the tip of the bullet when it's ready to fire.
No need to worry about chamber type.
Ideal AR Pistol Barrel Length?
- Thread starter calicojack
- Start date
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No need to worry about chamber type.
BCM upper.
04RWon
Ultimate Member
Excellent choice. If weight is a concern enhanced lightweight stuff is awesome, i tried the fluted for the 11.5. Its incredible. Very light when paired with their rail. I did keymod because it’s supposedly a tad lighter. I was trying to save every bit of weight possible. Its been very accurate too. Nothing special for a trigger, but the thing has been surprisingly accurate at 200 yards. Its eaten any ammo, tula included. Quickly becoming one of my favorites.
Hmm - I posted this in the rifle forum instead of the pistol forum. A Freudian slip on my part?
cdub702
Member
Dwell time is short on the 7.5 and they are finicky with different ammo, internals take much more abuse, its louder than hell (literally) some suppressors can handle it, ballistics are a pitiful, and unless you're under 5'5" the hand guard is going to be short for a average guy.I agree with the other guys 10.5 is the shortest I'll ever go with the 5.56, but 11.5 is the sweet spot for me, I cant remember the exact spec but I think the extra inch from 10.5-11.5 give you close to 30% increase in dwell time.
But if want to scare and annoy everyone at a indoor range and it's just a fun gun, definitely go 7.5"!!! KX3 flaming pig comp does take some of the crack out but remember any pistol will be stupid loud.
But if want to scare and annoy everyone at a indoor range and it's just a fun gun, definitely go 7.5"!!! KX3 flaming pig comp does take some of the crack out but remember any pistol will be stupid loud.
So the min and the "sweet spot" is about 8.5" and 9" for 300 black, and 10.5" and 11.5" for 5.56. Now to wait and watch for deals on an upper, preferably a BCM.
11.5" is definately sweeter than 10.5. I'm pretty sure Colt stopped making the 10.5 in favor of the 11.5.
I have owned both and sold the 10.5.
smokey
2A TEACHER
- Jan 31, 2008
- 31,497
- Jul 29, 2014
- 49,982
Only thing worth adding at this point, If you plan on attaching a suppressor, some cans have a minimum barrel length. Barrel length can whittle down your can choices.
Good to know - thanks.
AR Pistol Barrel Length
Generally accepted 10.5 inches is the shortest you should go on a 5.56 AR pistol because of muzzle flash and velocity loss, although some professionals won't go less than 11.5. At 500 yards a 55 grain bullet coming out of a 10.5 barrel is roughly equal to .22LR in energy. However, a 10.5 inch barrel is more a CQB gun and you can always use heavier (77 grain) bullets for adequate energy past 500 yards. With a non-collapsible arm brace it's possible with a 10.5 inch barrel to install a VFG if your overall length is at least 26 inches.
If you want to go shorter than 10.5 inches, I would recommend a 300 blackout upper. These are loaded for shorter barrels, don't have near the flash as a 5.56 and a 7.5 inch is adequate for most applications.
Generally accepted 10.5 inches is the shortest you should go on a 5.56 AR pistol because of muzzle flash and velocity loss, although some professionals won't go less than 11.5. At 500 yards a 55 grain bullet coming out of a 10.5 barrel is roughly equal to .22LR in energy. However, a 10.5 inch barrel is more a CQB gun and you can always use heavier (77 grain) bullets for adequate energy past 500 yards. With a non-collapsible arm brace it's possible with a 10.5 inch barrel to install a VFG if your overall length is at least 26 inches.
If you want to go shorter than 10.5 inches, I would recommend a 300 blackout upper. These are loaded for shorter barrels, don't have near the flash as a 5.56 and a 7.5 inch is adequate for most applications.
After the reports of the Mk18's long term reliability issues, I would absolutely not go under 11.5 on a DI AR-15 that was for serious work. Flash and muzzle velocity are almost secondary considerations compared to that.
Sent from my ZTE A2017U using Tapatalk
Sent from my ZTE A2017U using Tapatalk
If it has to be 5.56 those are sound choices for any serious use, simply because with 5.56 more FPS is better. and longer barrel means more FPS. Period. Full stop. Velocity is King...
For a range toy, it's not critical if its life is going to spent solely on plinking and amusement. Go with what makes you happy.
Shorter I'd think hard about 300BLK...That's what it was designed for, not a 20" barrel.
Blackstar65
Active Member
- Jun 27, 2010
- 996
I have a 12" ar15 pistol in 5.56. It has quickly become my favorite.
ralph.mclean
GOC (Grumpy Old Cop)
My 7.5 inch had a horrible muzzle blast issue. It was like getting blasted in the eyes with a camera flash from 3 feet away. Once I put a Kak flash can on it, it became a pleasure to shoot. My advice about barrel length is to decide what size suppressor you might eventually end up getting, and whether or you want to be able to extend a handguard out over it. In that case, the shorter the better...
FrankOceanXray
Ultimate Member
- Oct 29, 2008
- 12,036
Don't act like fireballs are not a good thing....
Answer is simple. Get multiple. 7.5 and 10.5 here.
smokey
2A TEACHER
- Jan 31, 2008
- 31,497
I fail to see a reason why I'd choose a 5.56 over a 300blk at barrels under 14" or so. You get much better performance in shorter barrels without the flash/bang. Once you add the thought of potentially suppressing it, it becomes a no-brainer.
- Jul 29, 2014
- 49,982
I have a Mk 18ish SBR I built with a 10.5" carbine gas barrel that has been flawless. From 5.56 to .223 handloads, it's handled them all, albeit suppressed. That's how the gun was designed.
ETA: This has nothing to do with you, erwos - Anyone considering short barreled rifle-ammunition guns needs to have realistic expectations. I chuckle whenever I hear 'velocity' mentioned in these threads. SBRs, whether pistols or carbines, are made for one primarily purpose. Urban-style combat. Clearing buildings, room by room. Secondarily, they can make good home defense weapons as well.
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