I am LEO and carry an AR-15 on duty daily. Rock River lower, Del-ton upper and internal parts, and several Magpul accessories. Other than range qualification, the most action the rifle has seen (so far) is this: (1) Beginning of shift: Function check, into the bag & trunk (2) End of shift: Out of the trunk, back into my locker Lately when I remove the magazine and function check, the mag has been REALLY tight in the well. So tight that it's difficult to depress the release button and strip the mag out. What's going on? They are cheapish metal mags... maybe it's time to upgrade to P-mags. Does the pressure of internal spring or constantly-loaded rounds push the metal outward over time? Or is there something in the mag well or lower receiver I should be looking at? Obviously I want this rifle to be in good working condition, should I ever need to deploy it!