I was interested in doing a 12.5 but the ballistics are the same as a 7.62x39 from the info I have gathered, correct me if I'm wrong.If you’re gonna go 13.7” or 14.5”, might as well do a pin and weld and not limit your options to a brace only. I’d only mess around with a pistol brace if I were gonna go 12.5” or shorter.

