I was inspired to build this from several instructables on building these type of 'plinking guns' I'm stealing the name for this particular one though, it's mine and I'll name her what I want. Earschplittzenloudenboomer more like earringingloudenpopper but w/e. It's my first instructable after like a year of loving this site.
It's made entirely of hobby shop sourced supplies
Brass tubing
Steel rod
Aluminum tubing
Torsion nut?
Popsicle stick
Super glue(cyanoacrylate gap filling glue actually)

Step 1: Get Some Things and Do Some Stuff

I just got some tubing from the hobby shop that fit snug but still a sliding fit, soldered a small bit of the rod inside the tubing and poked a hole for the fuse, made small strips of a Popsicle stick and made a body contoured to fit with the nut over the fuse hole and forward for access to reload, I scraped some primer from a .22 shell and used a piece of the same rod as a projectile. I just had some fuse laying around and I was itching to use it. I put a piece of brass inside two small pieces of aluminum for a scope and it's all super glued together, I then coated it again with glue and dropped it in the ashtray by accident and liked the effect so I left it.
It actually fires(with fuse) it fires small pieces of steel rod. I'd add a video but I jammed it with a misshapen projectile.
Nice project.