I just got my SU-22A and love it. I used Winchester High Velocity and experienced two jambs. I blame this on not "setting" the shells in the magazine. Haven't seen any other problems since a tap yhr bottom of the magazine before loading it. Can anyone tell me what magazine actually fits up into the butt stock on these. The 27 round is two bg and even the slim 30 round from black dog machine doesn't fit.