You should perhaps clarify the question a bit. I shoot AI's and TBAcs with a heavier barrel contour. I usually shim my brakes, but don't sweat the details (so if it's not perfect, I'd rather use less shims than more and a 180dg rotation-I liek it cinched up).. If you shoot 100% suppressed (I do), the brake position is cosmetic, the can always screws onto (clocks) the same position. Tat said, on my TBac cans and barrels, there is negligible POI shift (can on or off). TBac cans are light and have good tolerances which aid in repeatability, a heavier can on a lighter or CF barrel would likely yield different results. tbAC Zak or Ray are the better source.