Airsoft BB Magazine Problem?

You have a feeding issue. Usually spare magazines (if it was around 9$/9�) CAN have bad spring in them so when you wind your bb's, they may not be stored correctly so what may look like it will fire when you insert it into the gun, they will drop down again (a on on a mag is engaged when insterted into the gun so it can feed the bb's) thus resulting when you insert it, the bb's simply fall down again. Best thing to do would be to is take the mag apart (watch a vid on youtube) and get a new spring from your harware store. If that doesn't solve it, i haven't a clue sorry