The problem Black Jack is experiancing is caused by the cartridge stop. The assembly may be dirty, the spring may be weak, broken, installed wrong, or the stop itself may just be worn.
Try this, push the stop to the side with a screwdriver or pencil and then let it spring back, It should SNAP back into place under the mag tube opening. If it comes back slowly you've a spring or dirt problem, if it doesn't come back the spring is broken. If it snaps back then you've have a worn stop and it needs replaced.
A lot of these guns will function perfectly with no cartridge stop at all, if the AOL of the ammo is jist right! Strange but true! :shock: