hi
a lot of people have moaned about this gun jamming?, but this is person fault rather than product fault if you get my drift. personally i would take it to the shop,
if a pellet is jamming and stopping it, also is there a safety catch for the mag ?. then the only diy you could do is put a cleaning rod down and try to push it out. the help I'm offering is only what i have read on previous posts with similar problems ,but when it doubt take it to a gun smith this is the best advise you don't want to fook it up !!
hope this helps
regards
davy