42 posts
Joined September 2016

Adjusting the Crimp

How does one determine when they have the correct crimp setting at station #4?

This may seem like a dumb question to those more experienced, but I'm new at this and have no idea.


3,147 posts
Joined July 2007

RE: Adjusting the Crimp

It depends on if you are loading a revolver or semi-automatic cartridge. For revolvers, you want to curl the edge of the case mouth into the crimp groove or cannelure, so that if you drag a thumb nail down the edge, it doesn't catch at all on the edge of the case mouth.
Semi-automatic cartridges use a different style of crimp, called a taper crimp. Think of this as like sizing the case mouth enough to squeeze the edge of the case mouth snugly against the sides of the projectile. Calipers are your friend here. Your reloading manual will give you the maximum dimension at the case mouth. You usually want to crimp to a couple of thousanths smaller than this.
Here is a link to a good explanation.