Primarily less muzzle jump, than would normally be the case. Its been a while since I shot a Magnaported rifle, and I don't recall if the noise is as ojectionable as it is with a brake with reaward venting. It seems to me that the Magnaport vents the gases upwards and outwards rather than rearwards. You might find that the muzzle velocity is slightly lower than if the barrel was unvented, but this isn't written in stone.