Over tighting a muzzle break to time it can make the muzzle tight from the Vee threads torque compressing the muzzle. This is one reason why the flash hider wrench for the M1A/M14 was such a simple little stamping and not made as strong as some thought it should be. The added weight of the muzzle break added can affect a barrels harmonics. Browning had a set up that was adjustable for matching harmonics to a given load.