Legendary Lawman, SASS 73160

When I had that problem, after talking to Dillon, I could see that the primer punch was not dead center on the opening of the shellplate. Therefore, every so often as the primer punch came up, the primer edge would catch under the edge of the shellplate, tipping it sideways as it went in the primer pocket. I realigned it so that the punch came up exactly in the center of the shellplate opening. Problem solved (for me at least)