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Pneumatic Pen-gun Project

Built a miniature cannon? Then post it here! This section is for completed, finished cannons that you have built. Please include pictures and information.
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Unread postAuthor: frankrede » Fri May 11, 2007 10:10 pm

jackssmirkingrevenge wrote:
joannaardway wrote:Very innovative. This probably qualifies as one of the smallest spudguns in history.


Thanks :)

The smallest semi-amateur pneumatic I can think of is this device: pop-shot micro gun - chambered in 0.177 using the Brocock micro air cartridge (now illegal in the UK thanks to your lovely government :P) at about 900 psi.

I haven't seen a smaller co-axial though :D I could easily have gone smaller lengthwise but I wanted some measure of power.

I thought it said 300 psi and was made by a company
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Unread postAuthor: Hawkeye » Fri May 11, 2007 10:14 pm

It says 3000 and repeats it for emphasis...
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Unread postAuthor: ammosmoke » Fri May 11, 2007 10:46 pm

Yeah, didn't you catch that?
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<img>http://www.speedtest.net/result/309559995.png</img>
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Unread postAuthor: jackssmirkingrevenge » Sat May 12, 2007 12:04 am

Hawkeye wrote:It says 3000 and repeats it for emphasis...


It's bollocks as far as I can tell, usually the brocock micro cartridges aren't filled past 1000 psi, I know from other sources. I didn't see them checking it with a gauge either.

and was made by a company


In Pakistan? Not so, it was hand crafted by Steve Harper in the UK

After doing the math this little gun should blast a relatively standard weight pellet just over the speed of sound
if it had a barrel a bit over 2 inches in length.


Also bollocks, even with a rifle length barrel the full size tandem air cartridge could barely manage 12 ft/lbs, let alone break the sound barrier with its micro version and a tiny barrel.
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Unread postAuthor: ammosmoke » Sat May 12, 2007 12:11 am

Yeah, I'm gonna run it through GGDT and see what I get. Prob something similar to what you have. Man, they really must have exaggerated!!
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Unread postAuthor: jackssmirkingrevenge » Sat May 12, 2007 12:15 am

For reference' sake, this is what the cart looks like from the inside:

Image

(image taken from here)

It's fired by a firing pin striking the central stem and moving it forward.
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Unread postAuthor: jackssmirkingrevenge » Sat May 12, 2007 12:18 am

sorry for the double post, but here's the patent for the air cart as well
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Unread postAuthor: ammosmoke » Sat May 12, 2007 1:02 am

Well, IDK if its just me or what, but I can't get GGDT to run such small numbers successfully. It keep freaking out....

Image
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Unread postAuthor: frankrede » Sat May 12, 2007 1:40 am

Hawkeye wrote:It says 3000 and repeats it for emphasis...
I meant 3000
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Unread postAuthor: chaos » Sat May 12, 2007 2:12 am

ammosmoke wrote:Well, IDK if its just me or what, but I can't get GGDT to run such small numbers successfully. It keep freaking out....

Image


your projectile has a bigger diameter than the i-d of the barrel, and the reservoir data is wrong, somhow.
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Unread postAuthor: Hotwired » Sat May 12, 2007 5:37 am

Yeah... a 0.0177 projectile won't shift anywhere in a 0.0166 barrel.

Also, don't you mean 0.177?
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Unread postAuthor: jackssmirkingrevenge » Sat May 12, 2007 6:31 am

I'm being optimistic here, and only got half the speed of sound:
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using an earlier version of GGDT for simplicity's sake.
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Unread postAuthor: TwitchTheAussie » Sat May 12, 2007 8:17 am

Jack could you possibly make me one? I got $5 and some lollies :D But seriously how much do I have to pay to get one?
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spudgunning is like sex, once you've tasted, you can't wait til next time.
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Unread postAuthor: chaos » Sat May 12, 2007 8:30 am

can i put my order in, ill pay with some stainless tubing or something :D
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Unread postAuthor: jackssmirkingrevenge » Sat May 12, 2007 8:44 am

how much do I have to pay to get one?


Including postage to Oz, too much ;) sorry but I don't market complete launchers, besides, I'm already up to my ears in silencer orders at the moment.

However - honestly - I'm sure pretty much anyone could manage to build one. All you need is to rummage around your local model shop/hardware store for the right sizes of pipe, some decent 5 minute epoxy and a hacksaw.

You can use the money you saved to purchase a decent high-pressure shock pump :D
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