Steve, I know better than to unbalance good bullets by putting an uneven groove around them. There's no way that crimp will create the same groove depth and shape all the way around. Therefore, the bullet's center of mass has shifted. That will unbalance them more than they already are. They'll jump further off the muzzle axis when they exit; and they all won't jump off axis in the same direction. To say nothing of the inconsistant and heavier release force it creates that increases muzzle velocity spread as well as making the pressure curve different for each shot.
Ever measured the release force amount and spread for crimped bullets to uncrimped ones? I have. That alone should convince folks not to crimp their bullets in place.
US Navy Distinguished Marksman Badge 153
Former US Navy & Palma Rifle Team Member
NRA High Power Master & Long Range High Master
NRA Smallbore Prone Master