I have loads worked up already for my 9mm and AR. They do not currently have crimp. A buddy suggested I add crimp to keep the bullet from being pushed further into the case. If I add crimp to my rounds how will this affect the accuracy of my rounds? Would I have to redevelop or is there generally minimal impact made by a light crimp?
Question about adding crimp
- Thread starter mzvarner
- Start date
THIS^^^ I will add that you need a taper crimp die for your 9mm. I think the old-style roll crimp dies for autoloading pistol cartridges have about disappeared from the market. Your seating die should also crimp when adjusted properly, just make sure it says "taper crimp" on the die somewhere. I do not know for sure, but I think the Lee factory crimp die FOR PISTOL ROUNDS is simply a taper crimp die.
As far as rifle rounds, the majority seems to agree that crimping is not necessary. Personally, I crimp every round that may be used in an autoloader. Either a Lee Factory crimp die or a taper crimp die is all I would use. MOST seating dies for bottleneck rifle cartridges are ROLL CRIMP DIES and I do not recommend their use due to the probability of the random collapsed shoulder. Collapsed shoulders are the result of variations in case length and neck thickness.
I always seat and crimp in separate operations.
