This is a Yankee Hill Machine Co Part known as the Shim Set, model SHIM-3302-SET.
Barrel Shim Set to be used to correctly orient a timed muzzle device. This set is used with our 7.62mm Q.D. Muzzle Brakes. This shim kit has an inner diameter of 5/8"
Features:
Thicknesses included 2x 0.002, 3x 0.005, 1x 0.020"
