Thread: Roll crimping 308 subs

If you can achieve a 2 thou interference fit / neck tension and no crimp, that will produce the best results IME.

Your are spot on, with jacketed bullets the only cases that may need a crimp are the ones with short necks and very heavy recoil
then it would be prudent to use bullets with a cannelure and crimp in that,
bullets with out a cannelure should be crimped very carefully it is easy to over do it and damage the core,
Cast bullets should be crimped they don't have the same drag as jacketed bullets and slip out of the case neck with a lot less pressure
also soft lead bullets can be sized down when seating them if the neck is sized down to much, That is the reason to use a Lyman M die
not a Lee flaring tool.