I have a PM40 that I purchased used. About one out of 10 times, the cartridge doesn't feed fully into the barrel. It typically lacks about an 1/8 inch from fully seating.

The failure doesn't occur predictably - its not the first or the last bullet in the mag. The failure doesn't occur with any specific mag either.

I have replaced the recoil spring and guide assembly but this doesn't seem to have eliminated the problem.

When I extract the bullet that failed to feed, I have noticed a small "dent" or "gouge" mark on the bullet head. Typically on the edge of the bullet head.

Any ideas on what is going on?