Help-part 2

[divingin]

I suspect the bullet toppled to the side as you raised it into the seating die. It's happened to me even with boat tails . . . if the bullet is kind of resting on the case mouth, a slight motion can dislodge it and it can start into the die almost side-on.

I agree with this assessment.

A little more chamfer on the inside of the case mouth will allow the bullet base to sit slightly inside, and stay a little more stable as you raise the ram.