RCBS Gold Medal Match Series Bushing Neck Sizer Die for .308 Winchester

RCBS .308 Winchester Gold Medal Match Series Bushing Neck Sizer Die use precision-machined neck bushings (sold separately) to size the case neck just enough provide the exact amount of bullet tension without overworking the brass. To determine the proper neck bushing size, measure the outside neck diameter of a loaded cartridge and subtract .002" to .003" to allow for a small amount of brass spring back.