At the range yesterday and magazines were not dropping free. They were this past weekend at a match. I thought that it was plastic burrs in the magazine well from slamming metal magazines into a plastic gun. Sand papered the inside of mag well. This helped but did not solve sticking completely. I removed the interchangeable grip and mags would fall free. Appears that it is pinching sides of frame inward. I used a heat gun to warm the interchangeable grip and spread it then let it cool. It is better now. But what caused this? Are the plastic grips shrinking or warping with time? Anyone else have this problem?