[Brian Pfleuger]

The appearance if the primer is an unreliable indicator of pressure. I have used Federal SP primers that are so soft that they will flatten and mushroom at any charge level I have ever tried, while CCI SP primers show absolutely no signs of flattening at load levels considerably over published max loads.


Judging from that video, you have a major problem with your sizing die or those bullets are severely undersized. Do you have calipers? You should measure the sizing ring in that die, the size of your cases before and after sizing and the diameter if the bullets.