If BBs fall out of the gun when he releases the magazine, the magazine is not the problem. The only role of the magazine is to push BBs into the gun. The two failure points would be if the retainer is failing to be depressed (which it is not, as BBs are being released) or if the BBs are not feeding down into the gearing of the magazine (which they are not, as BBs are being released, thus, BBs are being driven upward into the channel).
I think your gun might be jammed, that or the hop is all the way on. It could just be the hopup rubber is on funny or some such. Maybe the tappet plate is busted. When you fire the gun with no magazine in, look into the magwell, is the nozzle moving back and forth (is a metal thing going into the hopup when you press the trigger)?
