How to Convert ANY Spud Gun Into a 12 Gauge Shotgun That Uses Shotgun Shells

   I discovered this with the first air cannon I ever built, which was made of 3/4 inch PVC. I noticed how perfectly a 12 gauge shotgun shell fit into the barrel and so basically I just cut the barrel an inch from the end and glued on a coupling so I could insert the shell, which I had to modify a bit. In this Instructable, you will learn how to convert pretty much any spud gun you have built, so long as it is made of PVC, into a 12 gauge shot gun that uses shells. Also, keep in mind that this is my first Instructable, so it might be a bit noobish. I hope that you find this helpful!

The materials needed are:

• 12 gauge shotgun shell casings (you can find these at a shooting range)

• 12 gauge shotgun shell wads (you can find these at a shooting range)

• 3/4 inch PVC pipe

• 3/4 inch PVC coupling 

• paper/cardboard 

• shot or whatever projectile(s) you want to use 

• drill

• scissors

• clamp 

• dowel

• hacksaw/PVC cutter

• PVC glue and primer

(N.B. if your barrel is made of a diameter of PVC that is different than 3/4 inch, you will also need a 3/4 inch adapter)

   This step is simple. If your air cannon is not 3/4 inch, add an adapter. Then, glue in your barrel and afterwards cut it at about 2 inches from the valve. Finally, glue in the 3/4 inch coupling to the small section of pipe and add your barrel. Do not glue the coupling to the barrel, glue it to the small section of pipe as this will make it a lot easier to extract the shell from the barrel. In the end, it should look kind of like the picture. 

   Now you need to make the shells. First, go to a shooting range and pick up some shotgun shells. There are a lot of lazy people who just leave them on the ground, so they should be easy to find. Wads, however, might be more difficult to find because they go really far down range in the skeet and trap zones. A good place to look is actually the rifle/pistol range because some people use shotguns there, and the wads are easy to find. 

   Next, you need to modify the shell a bit. Cut off the crimp, as this makes it easier to insert the wad, and then drill out the primer with a bit about the same diameter, so the air can get through. After that, inspect your wad; if you got it from a range, it probably would be really beat up. Cut off any pointy bits you see, and then jam it into the shell, using a dowel works great. Finally, put in your projectile(s) and then "crimp" the shell with a crumpled up piece of paper (don't use notebook paper, use thicker stuff like printer paper or thin cardboard); the "crimp" should be tight enough so that you can't hear the shot rattling if you shake the shell, but if it is too tight it might not fire. 

   Once the shell is completed, put it in the barrel and connect the barrel to the coupling. After that, you can fire the air cannon and at last you have turned your spud gun into a 12 gauge shotgun! So far I have only tested this with that air cannon I showed in one of the pictures, at about 60 PSI (it leaks really badly and it can hardly hold any pressure). I found that it can shoot BB's 25 yards or so, and marble slugs about 100 feet. Both can penetrate cardboard at 15-20 feet. The spread with BB's is close to two feet at maximum range, and slugs are surprisingly accurate considering I can't figure out how to make a choke for them. Darts are considerably more powerful with that spud gun, and I think the reason why it is weaker is because the BB's are such a heavy load and the design of a shotgun shell is quite inefficient at transferring energy. 

   Overall, I hope you have enjoyed my first Instructable. Please leave a comment about your results with this, improvements, or any other thoughts, all of which I would greatly appreciate. Thanks!