Building a Pneu

[Hubb]

I am currently designing a pneumatic cannon to use with paintball. The configuration will be that of a rifle and the barrel 1" sch 40. It will shoot about 10 paintballs at a time to give a small shotgun effect. It will be a revolver.

What I am wanting to know is opinion. Which would be cooler / more intimidating; a pump action or a semi-auto type?

Any input is welcome, especially from other paintballers.


Edit: Another question - The valve I plan on using with this will be a diaphragm. Will I notice an increase in performance if I were to add a burst disc valve after the diaphragm?

[Fnord]

What I am wanting to know is opinion. Which would be cooler / more intimidating; a pump action or a semi-auto type?

If the pump-action makes an authentic shotgun-cocking sound, that will.

[jackssmirkingrevenge]

Racking a pump action will always be more intimidating, but in a paintball scenario would you really want to stand in the open going *click CLICK* while everyone else is shooting at you?

Semi-auto would be the dog's danglies, but pump action will definitely be easier to make and more reliable, plus there's the added benefit of not having to use your limited on-board air supply to cycle the action.

I'm guessing what you want would look something likes this: http://rap4.com/paintball/os/rap4-revol ... p-931.html

Why not make it a combustion with pre-filled cartridges?

[noname]

You don't want 1" Sch 40 as a barrel, even if you want the paintballs to shotgun out all over. First, the ID is too small to allow more than one ball inside at once, so they have to be in single file. This will make the cartridges or whatever 6-8" long. 1" PVC is also a terrible fit for paintballs. If you want them to shotgun with a somewhat accurate grouping, use a 3/4" Sch 40 barrel. A 1" barrel will give you a 10+ foot spread from 20 feet away.

[Hubb]

I've thought and decided to go with pump action. I've also thought some more and decided to use 3/4" barrel.

This is my representation of how I would get the revolver to seal. It allows for the shells to fall into place without the pump having to be exact (which makes the build easier).

When the shell rotates, it compresses springs and it falls into the flared ends of the pipe. Once the shell is in place, the springs push against the shell and help to seal it and keep it aligned.

[spud yeti]

I think that pump action should be used for its ease and coolness, because I just built a semi-auto paintball (nearly done), and it was/is a mofo to build! Pump action is cool too, but I guess it depends what you want it for, "strategical and 1-shot" style, or "blast them to hell and back!", both having pros and cons.
I would recommend pump action though, even though semi-auto is awesome.

[paaiyan]

I have to say I would go pump on this one. I just want to see the look on someone's face when you stand behind them, *clickClick*. Surrender. Haha.

[spud yeti]

I have to say I would go pump on this one. I just want to see the look on someone's face when you stand behind them, *clickClick*. Surrender. Haha.

LOL, that would be awesome!

[paaiyan]

I have to say I would go pump on this one. I just want to see the look on someone's face when you stand behind them, *clickClick*. Surrender. Haha.

LOL, that would be awesome!

Of course it's awesome. Cause you know that shotgun cocking sound is the universal sound for, "You're pretty much hosed, just give up." If you do it you need to find a way to make it sound realistic, even if it doesn't add to the functionality of the gun.

And I can say as a paintballer, if someone just pops out with a semi, I'm gonna blow them away, but if I know someones hauling a PB shotty around and I hear it, I can safely say that I'd be diving for cover, cause God knows I don't want to get hit with 10 300FPS paintballs at once.

[spud yeti]

cause God knows I don't want to get hit with 10 300FPS paintballs at once.

Amen

I wonder how you could get the sound though, because its quite a 'heavy' click noise. Perhaps metal clicking past a spring loaded stopper (like on scooters to adjust the height, just a lot weaker)

[paaiyan]

I don't know, but I personally like the idea enough that I would try to get it just right. You may not care, that's just me.

[Hubb]

I was thinking along the same lines as paaiyan. The intimidation factor from a pump will outweigh the slightly faster shots of a semi. It will be PVC sliding against PVC but I will place a specially made noise maker just to make the noise.

Also, I was thinking of investing in a small spy type camera to mount on my paintball markers so I can capture the action.

"10 rounds of paint at once, $1. PVC cannon, $100. The look on the face of your next victim, priceless."

Oh. I was going to make it a revolver. What do you guys think about the sealing diagram above? Will it work?