Designed to be bored out for designated caliber 6mm - 30 Cal
Indexed ports to the side for prone shooting ; forward facing vent holes direct blast away from the shooter
.7255 OD and 1/2-28 TPI
PLEASE NOTE: These brakes are not pre-bored and need to be drilled to your specific caliber before installing and firing. Installation should be completed by a competent gunsmith.