I recently became the proud owner of a VFC mk16 and the gun is absolutely amazing. that being said it came with a small problem. it double feeds every time i fire the damn thing!? so i switched the bucking out and it still had feeding problems. i used midcaps highcaps and everytime the same thing. no modifications have been made to the gun internally in anyway. please help me, i thought about buying an all new hop up for it?