it's not really a "what's best" situation but rather what crimp does the slug and load data call for. Generally, Foster type take a roll crimp and Lyman (skirt / airgun pellet) take a fold crimp - at least based on the Lyman, BP and older manuals I've found, The LEE drive key being and exception.
It all depends on the equipment you have on hand or are willing to buy and how much pounding you want to take on your shoulder to find what your gun(s) like.



























