So I want to get a factory arsenal 5.56 or 7.62 sbr. I see that the factory ones are 28 7/8” But with a non permanently attached muzzle break. Any way to get that to 29”? I was looking at possibly getting the barrel re machined so I could put a jmac muzzle break to run a sandman. The factory arsenal muzzle break is 3.22” and the jmac is 2.82” so I think I would lose some length anything I can do?