Guys, need your help to figure this one out. Went to Armscor yesterday to shoot my baby armalite. After using up all the mags (five round strings per mag), I reloaded the first mag with 5 rounds and tried to insert it back into the gun. The mag would not go in. Upon closer inspection, it seems that the mag lips widened (mukhang bumuka), thus could no longer fit in the magazine port. Other two mags were OK all through out. Can you tell me what probably caused this? Thanks in advance!