I have a well used FEG GKK-45 that i really like, only problem is when i am shooting it, some times the Magazine pops out a little. Anyone seen this? I have the original clip thinking i might just try to replace that first.

Hmmm. Need more info. Are you seeing damage or wear in the area of the mag catch recess in the magazine? Have you taken a close look at the mag catch itself -- removed it from the gun for a close inspection? Does the mag slop around in the mag well? Does this only happen when it's fired? Have you considered the possibility that you may be accidentally tripping the mag release with your hand during firing? On that last note -- you could try being conscious of keeping your digits away from the release and see if the problem still presents itself. It still may relate to wear in part, but if you get a bit farther into this question please post an update and if I catch it I'll bounce some more ideas around. Good luck.

Several things mechanical could cause this -- a worn magazine, magazine catch, mag catch spring, etc.-- but the first piece of advice I always give anyone reporting the problem you describe is to check and double-check your thumb position each time you shoot. Quite often, the shooter is unintentionally punching the mag release.