RCBS Steel Neck Sizing Bushings provide precise tension on bullets when used with RCBS Gold Medal Match sizing dies, improving accuracy and prolonging case life.
Bushings should be selected based on the desired amount of neck tension; it's recommended to have sizes one to two above and below your target diameter.
To choose the correct bushing size, either subtract .002"-.003" from the loaded cartridge's outside neck diameter or calculate using case neck wall thickness plus bullet diameter minus .002"-.003".