I made this from a disassembled M16 airsoft rifle. This can be used as an object to reduce the weight on a ceiling, a pretend gun, a gun that actually shoots things, and can be modified for an infinite amount of other things.

MATERIALS:1 A 7" x 3/4" pipe (can be PVC, i used metal, also the pipe dimensions are slightly variable),
2 an easily stretchable spring:1 3/4" x 1/4",
3 a cocking device (pictured below)(I got it from the airsoft gun),
4 a bolt that is longer than the pipe's width,
5 a nut that fits the bolt,
6 philips head screwdriver,
7 and pliers.
8 if your pipe doesn't have holes in it like mine did, than you need a drill and bit that is slightly larger than your bolt.
9 if you don't have the cocking device, you can use a bolt that is longer that the pipe's width by atleast an inch or two

Step 1: Put the Cocking Device and Spring Together

i got both of these items from my airsoft gun. although you can find alternate items that will work. here you bend the last 2 turns in the spring at a 90 degree angle on both sides. the put the spring on the cocking device. you can also use a long bolt for the cocking device.

Step 2: Measure Bolt Width and Drill.

here, you should measure the bolt width and drill a slightly larger hole than the bolt. make sure you measure your trigger and spring in comparison to the drill hole so the trigger and spring will fit inside the pipe to the end of trigger. if you drill too big of a hole, you can use washers.

Step 3: Insert/attach Cocking Device

Just put the trigger and spring in the pipe so that one hole of the spring is in between the two holes of the pipe. put the bolt inthe first side of the pipe, through the spring hole, and through the back of the pipe. then tighten the bolt with the pliers and screwdriver.

<=/=/=/=D here the arrow at the beginning of this line is the tip, end of the bolt, the = sign is the bolt, the / is one side of the pipe, the = is still the bolt, the / is the spring hole, the = sign is the bolt, the / sign is the other end of the pipe, the = is the bolt, and the D is the head of the bolt.
make sure you attach the extended bolt or cocking device BEFORE you put the shorter bolt through the pipe, through the spring hole, and then through the other side of the pipe.

YOU'RE DONE! WOO-HOO