So ive been having this issue with my .40 PX4 Storm sub compact. Sometimes when firing the last round, the slide bites into the hard plastic of the magazine and fails to lock in the retracted position as it normally would when no rounds are left in the mag. You can see where the metal is catching the plastic but i dont know how to make it function smoothly. It apears to only happen with on of the mags. Any advice, ideas, or similar issues?