Only crimp for tubular magazines and weapons with exceptionally high cyclic rates, and elephant guns.
Never crimp a match bullet.
Crimping always swages the soft inner core of a bullet and will deform the jacket at some crimp level. Like what a Lee Crimp die did to these 6.5 SMK’s.
Deforming the core of a bullet and deforming the jacket will change the center of gravity. As that bullet rotates, with a center of gravity now outside the center of rotation, this will add inaccuracy.
No one, and I mean no one, who is a good competitive shooter, be it across the course, long range, bench rest, crimps their bullets. Period. I have been squadded with National Champs, I have friends who are national champs. No one crimps match bullets. If there was the slightest, tiniest tiny advantage, everyone would crimp.