In this instructable, I will show you how to make an air-powered sub machine gun. It is quick and easy to make!

Step 1: Materials

Materials:

PVC pipe (two 1½ inch elbows, one 1½ inch foot-long pipe)

Piece of Styrofoam (3 inches x 2 inches)

Hole puncher

Duct tape

1 piece of wood (6½ inches x 1½ inches)

Tripod

2 Liter soda bottle
Bicycle pump

Hot glue
Large marshmallows

Step 2: Soda Bottle

The soda bottle is where all the air is stored. The air is important to launch the marshmallows. You have to make sure there are no holes in the bottle besides the opening at the top.

Make a little hole in the middle of the bottle about the size of a needle.

Take one of the elbow pipes and hot glue it to the top of the bottle, where you would drink out of. Make sure the hole that you made is facing the floor and the elbow pipe is facing the left if you're holding it towards you.

Step 3: Barrel

Take the 1½ inch foot-long pipe. Attach the other elbow pipe so it is facing to the right.

Step 4: Connecting

Take the 6½ inches x 1½ inches piece of wood. Put the barrel on the left side of it so the elbow is facing to the right. Then put the soda bottle on the right of the wood so the elbow piece is facing to the left.

Step 5: Taping

Duct tape the barrel and soda bottle into place on the piece of wood. Make sure they can't move around.

(Hint: I used some masking tape as well to keep it in place better)

Step 6: Stand

Take the tripod and open it up so it is at a good height. Duct tape the piece of wood that has the barrel and soda bottle to the top of the tripod.

Step 7: Trigger

Take the piece of styrofoam. Hole punch many holes in one side of the styrofoam so there is one long line going down.

Insert the styrofoam in between the two elbow pipes.

Step 8: Shooting

You shoot the marshmallows by:

1)     Load the marshmallow in the front of the barrel.

2)     Insert the styrofoam trigger so the hole is sticking out. No air should be able to pass from the elbow of the soda bottle to the elbow of the barrel.

3)     Put the bicycle pump in the hole that you made. Make sure the pump's needle is sticking through the hole. No air should escape from the hole.

4)     Pump air into the bottle until you feel that it has enough air in it.

5)    Pull the trigger quickly so the hole is in between the elbow pipes.

6)     If you did it correctly, it should fire and the marshmallow should fly out!