I have a King Arms M4 and have a problem with my king arms mid cap mags. just before I went to vanguard they were working perfectly and suddenly when I get there lets just say 5 out of 10 only cycle they are all brand new and were all working fine I have a 6.03 madbull tighbore in it could that be part of the problem? it doesnt seem to be jamming though thanks:)