SpudFiles

I'm sorry. I was just too tired after I posted this cannon on SpudFiles last night to come and post it on here.

So, here we go!

This is a copper piston-valved marble gun I made in response to lowering temperatures. The chamber is 1x36" type M copper tubing, and the barrel is 1/2x48" type M copper tubing. Marbles fit REALLY well in this pipe. The average diameter of the marbles I've measured has so far been .566". The inside diameter of this tubing is .569". There were little dings in the barrel from construction, and I actually had to use a ramrod to get a marble down to the bottom for the first two or three shots. Now, they slide down, (usually), and then take a while to do it.

The power I've experienced when shooting this gun is awe-inspiring. I shot a marble almost clear through a paperback book, (video at the bottom), and blanks sound like a .22 CB round going off, (if anybody here doesn't know, the CB rounds are the shorter, quieter of the .22 rounds).

The valve is a barrel sealing tee valve. I made the piston by sharpening the end of a scrap length of 1" tubing and punching out a few 1/8" neoprene disks to make up the back centering plug and the front sealing face. I originally had some problems with the piston not sealing against the back of the barrel, but now it seals perfectly. The piston seal inside it's carriage aint to shabby either. I can pilot it by only halfway opening the 1/4" ball valve, with respectable power still.

Anyways, enough yip-yap, and more pictures! The money shot... An overview of the launcher
A view of the pilot and fill assembly
A view of the piston and the bumper
That's all the pictures I have. I also made a short video of me shooting through the paperback book, which is found here.

I'm also thinking about making some ballistics gel to shoot into. I got to work today, and it is extreme coincidence that the McMaster bill for all this copper came in yesterday, so I'll have to take money out the bank anyway. I'll probably do the actual shooting on Sunday, though.

Very nice, Brian will be proud. How much recoil you get?

Nice trombone!

What sort of pressure are you operating it at? I dont see a schrader valve anywhere. I take it you're charging it via the ball valve?

Seems a very nice gun. As already asked, what pressure did you use for that bookshot ? You should add a stock and some sort of sight.

PROUD?? HAHAHA
Well I do like how clean it is!!

Smooth, clean gun, looks like fun!!

Yeah, like I said on spudtech, it looks nice. Today was my second attempt at soldering. I was doing perfectly until the last weld.. the VERY LAST ONE!! I had dipped it in water to cool it down (it was a few minutes after the initial soldering). I tried to get it to work, but I just wouldnt. So I dropped it in water again, dried it, and tried again with no luck. Tried 1 final time, and ended up unsoldering the front bushing from the tee... Now I will need to replace a bunch of parts, and spend more money

I believe the problem was that the copper pieces were still a tiny bit wet, and this also caused nearby joints to unsolder themselves

Congrats, thats hell clean, same with the piston.
Keep it up.

That is a great solder job! Very Nice gun and its crazy strong.

Very nice. Much cleaner than my soldering, and the power is very notable.

Have you considered using steel ball bearings for ammo? They normally have much higher penetration than marbles, or so I find.

It makes me think of my twin's new copper piston cannon, although he did his with compression fittings and a 22mm barrel (20.2mm/.795" bore).

I'll badger him to register and post it on here.

Nice cannon,again i love the copper.Ever since i posted my gun with a bumper made from a tennis ball i seem to be seeing them more.What pressure is this cannon fired at?

What sort of pressure are you operating it at? I dont see a schrader valve anywhere. I take it you're charging it via the ball valve?

I usually charge er to around 120 PSIG through the male quick-disconnect on the ball valve, yes.

Have you considered using steel ball bearings for ammo? They normally have much higher penetration than marbles, or so I find.

I haven't seen those, and I don't wanna order just huge bearings off McMaster right now either. I was thinking more along the lines of lead sinkers...

Hi i want to know if you could tell me what that pison is made of (the rubber?)

Im disapointed in the sinkers that I have shot. when i shot at a peice of galvanized siding it turned out flat and left only a small dent in it. That was at 75 psi. A marble at 30 psi will go strait through.

Im guessing that it is some type of neopreme. You can use stuff that you find like i do. I took some rubber of a toy and used that as a sealing face.

rna_duelers wrote:Nice cannon,again i love the copper.Ever since i posted my gun with a bumper made from a tennis ball i seem to be seeing them more.What pressure is this cannon fired at?

Thats caus your his bloody idol, john

Actually... sorry to dissapoint you, rmich732 gave me the idea.