That is because you have too much crimp on that bullet! You are pushing the neck back and causing that protrusion on the shoulder.

Dispense with the crimp altogether, it isn’t necessary. Full length resize, seat the bullet to the correct depth and your cartridge should chamber fine. The correct depth isn’t necessarily to the cannular in the bullet. Set your bullet depth to where your bullet is about .030 inches back from the rifleing…

Montana seems to me to be what a small boy would think Texas is, listening to Texans..John Steinbeck