Step 1: Materials
Wooden circles, cut with a hole saw
Metal tubing, to fit your spring.
Endcap for the tubing
4.5mm copper, or any other metal tubing for barrel, 4.5mm is .177 for metal bb's or airgun darts, although if you wanted to fire plastic bb's you will need 6mm tubing i think.
I think thats it *thinking face*
Step 2: First step (not really step two)
Step 4: Step Three
Then, throught the hole in the middle, glue the 4mm dowweling in.
Screw a screw in the top of your circle, the slide the screw down your cutting in the springtube, therefore compressing the spring, and then twist to the side, locking in place, this is how you cock your gun.
Put this in your spring tube.
Step 5: Step 4
INstead of dowweling use 4.5mm (hollow!) copper/metal pipe do not block it off at all, this is your barrel
Glue the hole thing onto the other end of your tube, like an endcap. all done:)