[Marco Califo]

Crimp Rifle Bullets which have a crimping groove.

Crimped bullets should be used in auto-loaders to keep the bullet in placing during the working of the action.

If your bullets do not have crimping grooves, then you are loading for a bolt gun. In this case you can use a very little roll or taper crimp. Lee factory crimp dies are supposed to work for crimping bullets with out the cannelure, but this may compromise some bullets and Speer warns against doing this with their bullets.