Is it my imagination, or how the picture was taken, but the muzzle brake on the M5 looks as if the ports are up and down (vertical). They should be and are designed to be side to side (horizontal). If they are vertical the muzzle blast is directed up and down causing one heII of a blast into the sky and down into the bench or dirt if your prone. No such issue if ported side to side, other than foks next to you at the range may not like it as much.