RCBS 0.312" Neck Bushing

Designed for use with RCBS gold medal match series dies, these self-centering and interchangeable neck bushings let reloaders control neck tension with exactness, helping to extend brass longevity and improve accuracy by minimizing work hardening of the case neck. Achieving this precision does require brass with consistent neck wall thickness. The correct bushing size can be found by measuring the outside neck diameter of a loaded cartridge, then subtracting 0.002 - 0.003 inches , which accounts for 0.001 inches spring-back. Another method is to double the neck wall thickness, add the bullet diameter and subtract 0.001 inches. RCBS recommends having bushings slightly above and below your calculated size. Proudly made in the USA for superior quality and reliability