OK, I've seen a thread about this problem already, but I decided that due to the nature of the problem that it was worth doing another thread.
Now, onto the meat of this thread: Recently, I've been having trouble getting my G&P M16A1 and CYMA AIMS (CM.050) to feed. Both of them will fire correctly for a few shots and then nothing. When I fired the guns upside down, they feed properly, however. For the M16, I'm using G&P 360-round hi-caps, and for the AIMS, Matrix 600-round hi-caps. I don't want to say that the mags are the problem, but on the other hand, the M16 fired correctly with the stock mid-cap mag.
Any thoughts on the matter?