I have built 2 different uppers for my AR. One is a 10.5" and the other is 16" and both are 1:9 twist. I was out playing around at my brother's place and for some reason the 16" was louder than the 10.5". Why would that be?
Its an SRT typhoon. The only difference is the receiver themselves, the 10 is a YHM with an American Spirit barrel and the 16 is American Spirit on both the barrel and receiver