The gun noted in this Instructable has a trigger operated blue LED light inside the barrel. It shoots like a blue flashlight about 40 yards in the dark.
I did not photograph the process as I was constructing the gun, so I will try to recreate the steps in order to provide a clear instruction, the best I can. The basic gun and power pack took me abut 1 weekend. The holster took a few hours on another day.
As with most projects using found or old/recycle objects, you will find that you have access to slightly different materials. Adaptation, innovation and creativity are the keys to successfully completing the project with different materials.
Step 1: What you will need
Old BB gun - this was a 30 year old Daisy pump-action BB gun. This gun had the bb barrel over top of a pump section of the barrel. The top barrel was removed and just the pump portion used. Any single barrel gun should work as well. The barrel on my gun was about 3/4" outside diameter.
Old propane tank for barrel end- this is the type of propane tank used for soldering plumbing pipes, camp stoves, etc. There are similar sized tanks for mapp gas, etc. The tank was about 3" diameter x about 10" high. There is a 1" threaded top to attach the torch or other appliance
Sheet metal for reflector inside barrel end - I used left over aluminum flashing that was natural aluminum on one side and kind of gold on the other. I used the shiny aluminum side for the reflectors inside the barrel end.
Blue LED light, battery pack and some wire for the blue ion stream light
Plumbing fitting - 3/4" slip on to 1" threaded for connecting the barrel end to the gun barrel
Black rubber/plastic hose/tubing - I used 1/2" plastic tubing for connecting the gun to the powerpack
Wood for fabricating powerpack - 4" x 8" x 1 1/2" thick
Leather for the powerpack strap and holster (optional) - I got lucky and found a guy on craigslist selling a brown piece of leather left over from a motorcycle seat project.
Miscellaneous wood, hardware, fittings, etc. to be discussed later in the details
Below is a picture the original movie prop (I think) or replica that I found online. I understand the original was made from an Lee Enfield rifle (ala Call of Duty). Anyway, that is the prop I was trying to duplicate.