8.5 or 10.5 AR Pistol
- Thread starter lokidansk
- Start date
I shoot A LOT of SBR type rifles.
As a general rule i wont go shorter then 10.5" on a 556 gun...11.5" is even better.
My 300blk SBR is a 9" gun and thats a great length for that caliber.
Shorter then 10.5" in 556 gets really flashy and velocity starts to fall too far off the norm for those little bullets.
As a purely rangetoy.... 7" barrels can be made to run ok. Not a lot of fun in my book. Double up on earpro and dont mind the nasty looks you get from other shooters.
As a general rule i wont go shorter then 10.5" on a 556 gun...11.5" is even better.
My 300blk SBR is a 9" gun and thats a great length for that caliber.
Shorter then 10.5" in 556 gets really flashy and velocity starts to fall too far off the norm for those little bullets.
As a purely rangetoy.... 7" barrels can be made to run ok. Not a lot of fun in my book. Double up on earpro and dont mind the nasty looks you get from other shooters.
PSA 10.5" Uppers
I have two of the PSA 10.5" uppers and my son has an 11.5". Have not had any reliability problems with either barrel length. I cannot tell the difference when shooting tbem in either recoil muzzle flash. Two of the lowers have KAK Shockwave braces and one has a Sig brace. We both much prefer the Shockwave.
I have two of the PSA 10.5" uppers and my son has an 11.5". Have not had any reliability problems with either barrel length. I cannot tell the difference when shooting tbem in either recoil muzzle flash. Two of the lowers have KAK Shockwave braces and one has a Sig brace. We both much prefer the Shockwave.
I've got a few uppers from these guys. Great quality and prices. https://www.hardenedarms.com/ecCat_36
I have an 11.5 upper I assembled that works great. It is about as short as an AR needs to be. I went with that length because many people on many forums recommended that as the minimum length. I got my barrel from Knesek as there weren't many other options available at the time, but today many manufacturers are making 11.5" bbls. Try Ballistic Advantage if you plan on making your own.
I went 10.5". First the US Army settled on that as the minimum length barrel for use back in 1965. That is entirely due to it being the shortest length barrel that still produces effective ballistic results with minimum operator difficulty and the highest reliability. Even then the follow on models got sound moderators which are now classed as silencers. Shorter barrels are much more ineffective - the point of the gun is to be able to launch a bullet at a live target and stop it from fighting back. 10.5" does that, shorter barrels don't and the effectiveness drops rapidly .
Second it's long enough to actually grip forward of the magazine in a useful manner, which helps stabilize the sight picture. There's enough to grip and also mount optics or accessories. It's long enough with carbine gas to accept carbine length handguards, and I don't need expensive custom length ones.
In total that's why it's still the preferred military weapon for ship boarding and clearing parties or use in restricted urban areas - the same conditions as it was meant to be used in Vietnam, tight quarters with the enemy close at hand. Being short it had the advantage compared to the AK47 or even longer SKS in close combat.
I built mine as a 10.5 with carbine gas and B5 handguards with FSB and a Black River Tactical linear on it. Weighs 5.5 pounds and cost less than $100 a pound to build. Somebody buried a brake under an expensive float on one and it turned out ugly: http://www.thefirearmblog.com/blog/2016/06/14/potd-3/ An 8" would have had another 25% higher gas velocity with even more damage. You can go too short.
Second it's long enough to actually grip forward of the magazine in a useful manner, which helps stabilize the sight picture. There's enough to grip and also mount optics or accessories. It's long enough with carbine gas to accept carbine length handguards, and I don't need expensive custom length ones.
In total that's why it's still the preferred military weapon for ship boarding and clearing parties or use in restricted urban areas - the same conditions as it was meant to be used in Vietnam, tight quarters with the enemy close at hand. Being short it had the advantage compared to the AK47 or even longer SKS in close combat.
I built mine as a 10.5 with carbine gas and B5 handguards with FSB and a Black River Tactical linear on it. Weighs 5.5 pounds and cost less than $100 a pound to build. Somebody buried a brake under an expensive float on one and it turned out ugly: http://www.thefirearmblog.com/blog/2016/06/14/potd-3/ An 8" would have had another 25% higher gas velocity with even more damage. You can go too short.
jbrannon54
New member
I couldn't ever figure out how to make my own thread, but I have a question if someone is willing. I don't have anything built yet, but say I had an AR15 with a 10.5 inch barrel on the upper, with a vertical fore grip on it. Also have an extension stock on the lower. When it is fully extended it is 28 inches long (overal 26 inches). What would this AR be classified as? SBR? Pistol? Rifle?
