Neck Bushings Not Included
RCBS is proud to introduce the Gold Medal series of neck bushing rifle dies. This changeable diameter neck bushing type of die has been used by Bench Rest and Long Range Precision shooters for years.
Due to variability in neck brass thickness, RCBS standard dies size the neck below your desired diameter and then pull an expander ball through to get the proper bullet tension. The Gold Medal sizing die features a self centering, changeable neck bushing that allows you to precisely set the
amount of tension on the bullet. This reduces work hardening of the case neck brass, prolonging case life and increasing accuracy. Neck bushings are available in .001 increments from .189 to .365.
Proper neck bushing size can be determined two ways. Measure the outside neck diameter of your loaded cartridge, subtract .002 to .003. This allows approximately .001 of brass spring back for correct neck tension. The other is to measure the neck wall thickness of your case, multiply by two, add the diameter of your bullet and subtract .001. RCBS suggests that you have neck bushings one to two sizes above and below your target diameter.