Anyone having problems with the magazines locking up in their pistol. The magazine I received with my match works fine but the two I purchased from midway will not lock up on the magazine release. They appear to have a different floor plate then the one that came with the gun. The original one is totally flat while the two newer ones have a slight curve to the front of the floor plate. when you field strip them and put them in the gun without the guts they lock up fine. Help!!