I agree with Grim Reaper on this. My son just got started reloading and i gave him my old Dillon and some supplies. He didn't listen to me and forgot to chamferr the inside of the case mouth. I went to pull a bullet to check his powder charge and as hard as i tried i couldn't get that bullet out. This was a Montana gold FMJ so no hole for the lead to come out. I imagine if the mouth is gripping the jacket with a strong crimp that the lead could come out with enoigh hits of the kinetic puller. If there are enough burrs on the case mouth they will dig into the jacket and bite like a bear trap when crimped