Thread: Choosing Correct Bushing for Neck sizing

Originally Posted by rupert

The neck wall thickness does not change after firing. However, after you have fired each case several times, the spring back of the neck will alter as the hardness of the brass increases with multiple firings. So, the case will need a smaller bushing, than used initially, to create enough tension in the neck to hold the bullet consistently. I prefer a bushing smaller than the loaded round by 0.002 - 0.003" for hunting rounds because I don't want the bullets to shift in the cartridge case necks due to recoil while in the magazine. Different bullet designs may have slightly different diameters (same nominal calibre) due to the way different designs are manufactured which may affect the amount of tension/bushing size. It may be beneficial to turn the case necks down to a uniform thickness for use in the bushing die.

OK cool, might grab a .312 as well.

I assume annealing would mitigate the work hardened brass issue a bit?