I know exactly what the problem is - its an AR 15!
Sorry, I couldn't resist...
Seriously though, mags are always the most likely culprit. There is an element of truth to my first comment too, but constantly jamming when the weapon isnt that dirty isnt a "normal" f2f or f2e issue, something is going on.
"They who can give up essential liberty to obtain a little temporary safety, deserve neither liberty nor safety. - B. Franklin"