A zip gun is a homemade weapon that is commonly made using a pipe for the barrel. The stock of the zip gun holds the barrel in position and can be made from any of a number of devices. Using a steel stapler as the zip gun's stock provides for a more solid construction that is less likely to fall apart when the bullet is fired. Zip guns are potentially dangerous as they can blow up in use and so should never be handheld if fired.
Drill a 15/64-inch-wide hole 9/16 of an inch deep into the end of the solid 1/8-inch pipe plug. Screw the pipe plug into the steel pipe coupling.
Insert this pipe assembly into the 6-inch steel pipe.
Cut the other end of the steel pipe so that it is just a little bit longer than the pipe assembly now inside of it.
Drill a hole off-center in the pipe plug, at the square end, that is large enough for the nail to go through.
Push the nail through the pipe plug until the head of the nail is flush with the square end.
Screw the pipe plug onto the steel pipe with the flush square end facing outward and the nail inside.
Place the pipe onto the top of the stapler with the open end of the pipe at the end where the stapler's head is. Glue the pipe to the stapler using the bonding glue. Let the glue dry.
Bend the metal strap into a "U" shape. Drill a hole in each of the ends of the metal strap.
Put the metal strap on top of the stapler and at the back of the rod so that it is an inch away from the nail.
Insert the small metal rod into the two holes of the metal strap. Secure the rod to the metal strap using the lug nuts.
Push the metal strap against the nail to pretend to fire the zip gun's bullet that has been placed inside of the steel rod.