SpudFiles

This pneumatic rifle uses a 2" piston valve actuated by a 1/4" ball valve as a firing mechanism. The piston itself is made from a 1.5" PVC cap filled with epoxy with the rubber sealing face sitting inside. Sidewalk chalk and wooden dowels are the primary ammo. The gun was finished in July of 2008 and has since been upgraded to add the scope, muzzle break, and rifled barrel.

Stats

• *Total length: 72 in
  *Barrel length: 52 in
  *Barrel diameter: 1.0 in
  *Chamber volume: 80 in³
  *Max pressure: 120 psi

Features

• *Rifled barrel
  *Breach loading barrel (slide & lock)
  *Stock
  *Scope w/ cross-hairs (no zoom)
  *Muzzle break
  *Bipod

[youtube][/youtube]

This is a very nice build !

The chamber is a little too much big for the barrel tough.
Try putting on a bigger barrel (it would give some nice recoil).

Very nice. How is the rifled barrel, have you compared it to a smooth barrel ?

For accurate target shooting the piloting time and projectiles would have to be very consistent. As you are using it at 120psi you could quite easily have it solenoid piloted.
Heavier projectiles might also prove to be more accurate.

I love the sound it makes on the video, is it like that in real life ?

Wow I have to say that this is an awesome creation! I love the way that the stock and the valve assembly blend together smoothly.

I think that using the tee connector as a muzzle brake might be the cause of that cool noise that the launcher makes. This launcher that I made has a similar muzzle brake and makes the same type of noise.

Very nice build! I like it! You might wanna consider repalcing the ball valve with some other pilot for better accuracy.

I love the sound it makes on the video, is it like that in real life ?

Ditto

wow thats awesome!!, i love the way you attached the scope!

I love the sound it makes on the video, is it like that in real life ?

i agree, sounds a lot like a well built rifle!

What are the little brass fittings called?

Looks good. How good does the rifled barrel work?

The muzzle break really changes the sound of the gun and gives it that high-pitched character. Without it, you get more of a loud pop.

In case anyone is curious, the barrel was rifled using a long wooden dowel with 4 wood screws in it. It was driven through the inside of the barrel with a hammer and twisted along the way down at a constant rate (3 passes were made). Similar techniques have already been described on the how-to forum.

We actually have a smoothbore barrel we were using with the gun to compare accuracy with the rifled one. In general, it was found that the rifled barrel had noticeably better accuracy as long as the projectile was snug and it's surface was something soft enough to be cut by the rifling. In the youtube video, we were using sidewalk chalk wrapped in tape to fit tightly. They at least seemed to fly fairly straight.

What are the little brass fittings called?

Brass pipe fittings or compression fittings. Any hadware store with a halfway decent plumbing section will have a good selection of these. Carefull though, they can be a bit pricey!

sidewalk chalk wrapped in tape

hmm interesting choice of ammo

I was just about to chew you out for using DWV, until i realized.... you dont have any pressure in the dwv, you just used it for the stock.... and then i was like..... woah... the proper use for DWV....

Well made, why not hide a proper cheapo 4x20 scope in the housing?

how did you reduce to the 1/4 inch ball valve from the piston??? can you post a a diagram???

Its an old topic so you should pm the creator, but it looks like he tapped the threads.