To make your own bandgun ammo, you will need some surgical tubing 1/4" inner diameter with an outside wall 1/16th" thick. Cut a section long enough to match your existing ammo with a one-inch overlap of the rubber ends. One side should be cut diagonally.

Slide the straight-cut end of the rubber tube over an awl, phillips-head screwdriver, or something else of that nature. Now roll the end down over itself, making sure to roll it back enough so you can roll an inch's worth over material over the other end.

Holding the rolled end in place so that it doesn't snap back into it's original unrolled form, slide it off the awl and put the tip of the diagonally-cut end into the rolled end. Now roll the flat-cut end down over the diagonally-cut end, creating an overlap that should hold itself in place.

This now needs to be reinforced so that the diagonally-cut end doesn't slip out of the other end when pulled. Tighten two zip ties around the overlapping part, clip off most of the excess zip tie. Now wrap some duct tape over this. The duct tape will halp to keep the zip ties from coming apart, but more importantly, it will keep the band from being damaged by the metal muzzle it is stretched over again and again. Use a bright color of duct tape so that you can easily find the band after you fire it. I usually use white, bright blue, or hunter orange tape.

*An idea that was posed to me, in effort to help the band fly straighter, is to put about a teaspoon of fine sand into the rubber tubing before coupling it. This, theoretically, disperses as the band spins through the air, and helps it to fly straighter. I've not done this myself, but some people have found it effective.