Measure the ball or plug in your expander die. It is almost surely too large in diameter for the bullet you are using. You can turn it down in a drill until it's 3 or 4 thous. smaller than your bullet. You should be able to seat a bullet and press the nose of the cartridge against the edge of your bench hard and it should not move (before crimping). If it does your expander is too big. If your expander is correctly sized and you still see bullet movement then your sizing die is out of spec (not sizing down enough) And Remington brass is made from from thin brass. Avoid it. On semi auto rounds the crimp serves only to remove the flare. It does not hold the bullet in the case.
Last edited by drail; September 23, 2012 at 01:08 PM.