PPK question

[44man]

My friend brought his PPK .380 over. It is the stainless, made in USA model. Every time he shoots it, the magazine pops out. I can't find anything wrong and I can't make it happen if I shoot 50 rounds. The follower was just touching the latch so I took a diamond wheel and just trimmed it a tad but that did not help. He has the problem at anytime during a magazine full, not at one place. He will shoot and turn to show me the thing sticking down a little.
Any ideas?

[400cor-bon]

If you cant make it happen,
maybe he is hitting the mag release on recoil or the way he grips the gun?