Things You'll Need
Instructions
Clean out a pump-action water gun with warm soap and water. This will help remove any type of dirt or build-up so that the air pressure will fire the pellets correctly.
Buy a hollow metal tube and inspect it to make sure there is no rust or other damage. Make sure this tube has a bigger diameter than the pellets you plan to fire.
Heat a hot glue gun and glue the tube to the barrel of the water gun, where the water comes out. Hold the tube in place for a good 15 seconds or longer so that the glue has time to bond. Allow a few hours for the glue to fully harden.
Drop a pellet down the open end of the tube so that it rests against the end of the barrel of the water gun.
Pump the water gun a few times. This allows air pressure to build up in the gun, which is what will fire your pellet. Aim the gun at your target and pull the trigger.