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I need a new project!

A place to ask general spud cannon related questions.
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I need a new project!

Unread postAuthor: sharpshooter » Thu Jul 12, 2007 3:01 pm

I'm running out of things to do, so i end up spending to much time on the computer =[

Ive already made 12 combustions, 6 pneumatics, 3 hybrids, dozens of BBMGs, 4 hover craft, a pump airsoft shotgun, and countless other random useless pieces of junk.

I need an idea.

I was thinkin some sort of semi auto. maybe along the lines of a .5" barrel.

Any one have any ideas for how i could get a rifled barrel somewhere close to this size with out spending an arm and a leg? And of course, the corresponding ammo.

If this gun is gonna b useful, it'll have to be portable... so CO2 powered it is. Maybe a copper piston running at about 200psi? How much can a QEV take? whats a good source for those (sadly... i could never find one for my guns =[... then again i never looked to hard). What about a hammer valve from a paint ball gun? do they provide enough flow for something heavier than a paint ball?

Im thinking a clip or magazine fed gun. Using a few small springs to push the bullets up. maybe something like mcmaster part #9657K79??? Lol... i still need to figure out the ammo.

I need something that is going to be accurate. Im open to suggestions.

sorry for rambling////brainstorming out loud

Ok So... to recap.

Copper pneumatic. 95% sure itll be over/under. QEV or piston for a valve. CO2 powered possibly in the 200-300 psi range (i do have the required regs already). Clip fed, semi auto.

This gun must be portable, accurate, powerful.

need suggestions on barrel/ammo. whats the most accurate, most powerful combo?

Is there much improvement between 100 or 200 or 300 psi? All depends on chamber size im guessing.

thanks guys 8)
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Unread postAuthor: spud yeti » Thu Jul 12, 2007 3:28 pm

Sounds like a cool idea.
A QEV can only take like 150PSI or less I think.
I would suggest a really nice piston valve or diaphram valve. Remember that then you are going to need a corresponding valve to allow for semi-auto (think of clides slider, gb cannon etc).
I thought you could buy 1/2" pvc, cant you?
What about non-round ammo and creating a shell-like bullet and magazine feed?
All these are just suggestions, so ask for anything else!
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really good quote/phrase here
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Unread postAuthor: VH_man » Thu Jul 12, 2007 3:50 pm

i would go with blowgun darts, if you want accuracy and power.....

semi-auto might be a little hard. i reccomend bolt action instead, youre still gonna get an amazing ROF outta that.

make sure you rifle your barrel!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! (if youre going to use round ammo....)
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Unread postAuthor: frankrede » Thu Jul 12, 2007 4:12 pm

Semi auto is not hard at all, all you need is a paddle type interrupter and a upright magazine.
No fancy loading mechanisms, nothing.
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Unread postAuthor: noname » Thu Jul 12, 2007 4:26 pm

Invent a new type of strafer!

That's what I'm doing......
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Unread postAuthor: sharpshooter » Thu Jul 12, 2007 8:30 pm

how would i go about rifling a barrel? If i could do that, that would change a lot of things.

I wanted to use copper A) because i never have B) u can still attach directly to it C) ridged, unlike small PVC

I guess piston it will be. Lathed PVC stock best? or is there something better?

Darts could work... are you talking like blow gun kina things or modified bow/arrow things?

How high of pressure can i go with regular copper pipe? (like from ace or Menard's) or do i need to get something better?

Ive already done a pump and a bolt (actually... 2 bolts) so itll be semi.

Would i get good accuracy out of something like marbles or glass sling shot, with a hop up type deal?

actually... lets put this in order.

1) rifled barrel, longer bullet/missile shaped
2) smooth barrel, darts
3)hop up, sphere ammo
4)smooth barrel, sphere ammo
5)smooth barrel, longer bullet/missile shaped

Does that make sense?? should i move/add anything??
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Unread postAuthor: sharpshooter » Thu Jul 12, 2007 11:10 pm

alright. So i went to handy dandy paint and drew something up.

This would b using copper pipe of various sizes. It has a split chamber, which could be used to hold the clip steady. The main thing to this is the blue bolt. To allow air through, it must be pushed forward to the wider area, air then can flow through the holes in it (light blue). The bolt sliding forward makes sure only one projectile is engaged, and then is returned wen the air escapes by a spring (red) of some sort (i haven't worked out the math yet to know how strong of spring).

The clip is quite simple, just a hollow rectangle, a weak spring (red again) and a little platform (green) for the ammo.

The ammo is just kina a picture to take up space, as of right now im leaning towards a blowgun type dart. Not the ones at stores that are a stick and a plastic thing, but something heavier with yarn/string on the end

The piston will most likely be cast out of resin or epoxy, as i do not have access to a lathe until school starts again. O rings and some sort of rubber on the front will keep it sealed (both grey). The chamber is filled with co2 through the yellow/gold fitting (either a male quick disconnect, a hose barb, or a steel braided line threaded in)

As you can see, the co2 setup is not pictured, just because I'm too lazy.

Im open to any comments/questions/criticism/suggestions
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Unread postAuthor: VH_man » Fri Jul 13, 2007 5:42 am

round spherical ammo is going to be easier to make a feed mechanism for.

go with 1/2 inch copper, 14mm marbles, and a peice of craft foam superglued into the breech end of your barrel, about 2 inches long to act as a hop-up.

and sharpshooter, there are easier ways to make a blow-foward bolt.

Ill get around to posting one eventually.
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