New project: Homemade Nerf Gun.
This idea started with a toy pump used for pumping up an air-powered airplane. I attached a length of 1/2" PVC pipe to the end to accommodate Nerf darts, and rigged up a system to power the entire mechanism via bungee cord. It was a basic bow and arrow, and was operated in the same way.
General view of the gun. The black pump, white PVC barrel, steel reinforcement are clearly visible. As is the bungee cord, which hooks onto the bent metal thing on the end of the barrel.
Back view of gun -- reinforcement visible.
A bolt on the handle serves to stop the plunger from impacting the PVC barrel inside the pump, as doing so propels the barrel out from the frame like a bullet.
The connection between pump and barrel. Both were whittled and filed down to fit each other, as it is a dry fit.
Front view of gun -- barrel, reinforcement, and bungee anchor are visible.
The result of firing the gun with the bolt on the handle in place. It placed all the stress on the outer casing of the pump, and it cracked a few inches.
I'm currently working on a new design that will be considerably more complex and will be spring-powered.