View Full Version : AR Uppers - Pistol uppers vs SBR uppers

09-22-2010, 2:07 PM
Ive been looking to get a AR pistol, but see anything from 7.5" to 11" uppers.

Is there any difference between a pistol upper and an SBR upper?

What would you recommend as the minimum length for a 5.56 cartridge? From what I read, you have a lot to loose in terms of peformance shorter you go.

Whats the best length for a Pistol upper without getting into the SBR type of lengths.

gun toting monkeyboy
09-22-2010, 2:11 PM
There is no difference in the uppers. It is simply a matter of which lower you put it on. Any barrel under 16" long can't be put on anything with a rifle stock without going through the ATF and their SBR process. Which is exceedingly unlikely to happen here in CA. If the barrel is under 16" here in California, you have 2 options. 1) Attach a flashhider/muzzle brake to the end of it and have it permanantly mounted to the barrel to make the overall length greater than 16". Or 2) Mount the upper on a legal pistol lower, and call the whole thing a pistol.

As for what length, that is purely up to you. The more you shorten the barrel, the more power you lose. 11.5" seems to be the norm, but there are versions out there with 6-8" barrels that some people like. I went with 10.5", and it is loud, with a huge fireball. I have no idea what the velocity is like. It is fun to shoot, but not especially useful.

09-22-2010, 2:22 PM
Some 10.5" and 11.5" uppers are called commando length and use a carbine gas system.

Shorter barrels usually have a pistol gas system that is shorter than the carbine setup.