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semi-auto or bolt action

Post questions and info about pneumatic (compressed gas) powered cannons here. This includes discussion about valves, pipe types, compressors, alternate gas setups, and anything else relevant.
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Is it possible?

Poll ended at Mon Jul 02, 2007 12:20 pm

Easily
4
33%
May be difficult
6
50%
Just give up now
1
8%
Just give up now
1
8%
 
Total votes : 12
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semi-auto or bolt action

Unread postAuthor: knappengineering » Wed Jun 27, 2007 12:20 pm

I was thinking of making a gun that is semi-auto. It will be hooked up to a compressor for constant air pressure, but I don't know how to make the ammunition load automatically like from a magazine. Any1 have any ideas?
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Last edited by knappengineering on Wed Jun 27, 2007 8:29 pm, edited 1 time in total.
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Unread postAuthor: hi » Wed Jun 27, 2007 12:22 pm

that i know of, only one person on this forum had done that and that is clide.

im not saying that others havent, im just saying that is the only one i know of. to answer your question, its not that easy.
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Re: semi-auto

Unread postAuthor: jackssmirkingrevenge » Wed Jun 27, 2007 12:23 pm

knappengineering wrote:Any1 have any ideas?


Here's one :)
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Unread postAuthor: Pete Zaria » Wed Jun 27, 2007 5:12 pm

@knappengineering,

First of all, I assume we're talking about pneumatics here (doing a semi-auto combustion is much more difficult due to heat and venting problems, though check out "Revolver X").

The valve and air chamber setups are simple enough, given that you have a heavy-duty compressor. The difficult part becomes the automatic reloading mechanism.

If you wouldn't mind a bolt-action (you have to move the bolt forward and backward again between each shot, but that only takes half a second...), that's much more feasible. Technically this is not semi-automatic, but it's getting much closer.
BCArms sells a great golf ball bolt action for $17 or so, I believe.

Another option is to try to make a gas-blowback type system to automatically rack the bolt on the reloading mechanism. This seems to require reasonably high pressures, and intricate design that is beyond the capibility of most people on this site without a well-equipped machine shop.

Look around this site, there have been a few guns that might classify as "semiautomatic", Clide's golfball gun first and foremost, but there are others if you look around.

Hope that's helpful.

Peace,
Pete Zaria.
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Unread postAuthor: wannabie » Wed Jun 27, 2007 5:26 pm

http://www.spudfiles.com/forums/full-au ... t4108.html

Theres an idea just dont go and copy the gun completely that would be bad... :roll:
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Unread postAuthor: knappengineering » Wed Jun 27, 2007 8:23 pm

A bolt-action would be great! :lol: Does any1 know how to make a bolt action for a half inch barrel?
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Unread postAuthor: Infernal Maveric » Thu Jun 28, 2007 2:25 am

Here is a bolt action I drew up on paint.

Image

The housing could be a coupling or a larger peiece of pipe that is attatched to a 1/2" barrel.

The piston would either need to be machined or done good ol' DIY style
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Unread postAuthor: spud yeti » Thu Jun 28, 2007 2:36 am

I am in the process of completing my semi auto paintball and came up with a decent method of loading.
I have all the info about it on my website, so if you'd care to take a look at it, its all there!
Please just dont claim it as your own...my precious! :D
Its under the "Cannons" section and "semi auto paintball gun"
feel free to look around too! :D
Hope it helps!
Infernal Maveric: I can only see one problem with your design. That is that you cannot control the amount of balls flowing into the barrel once the piston is opened. Am i right, or just being stupid?!
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really good quote/phrase here
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Unread postAuthor: Infernal Maveric » Thu Jun 28, 2007 4:34 am

Yeti you have a point, but dont forget that as soon as the piston slides back to drop ammo down, the air will shoot the ammo out in milliseconds, thus resulting in the bolt sliding back to cover the feed hole.

I havn't made a semi with this design, but i know that some-one (not on these forums) made a semi auto BB gun from a FE and some acrylic for the piston housing. It has been posted here somewhere, but I'm lazy to look.
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Unread postAuthor: spud yeti » Thu Jun 28, 2007 4:46 am

Its true what youre saying about the speed its going to be shot, but Im thinking there is chance that a ball could get caught halfway down and jam the gun and cause a mess. I also have a problem that the hole is exposed when the air passes it and this will waste your air thats supposed to be going out the barrel, and you will lose performance. I think from that aspect my design is more practical, but I dont want to brag or anything... I guess its all about opinions...
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really good quote/phrase here
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Unread postAuthor: From_Hamsterdam » Thu Jun 28, 2007 4:56 am

this is my semi i just need an compressor and it should work
http://www.spudfiles.com/forums/semi-co ... t8892.html
it uses shells making it more complex then just firing the ammo by it self.

try looking for "blow forward bolt"
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Unread postAuthor: spud yeti » Thu Jun 28, 2007 5:05 am

nice gun man! i really like it.
btw, you havent answered my questions on that topic! :D shocking! :D
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really good quote/phrase here
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Unread postAuthor: lukemc » Thu Jun 28, 2007 8:09 am

i would say just mak a bolt. fin any cylinder that fits in brarrel snugly but not real tight, if you cant find anything you could mold it out of epoxy or something . then drill as big of a hole as you can thought it but make sure it stays intact. finaly cut a groove in the barrel where you want your bolt to go, put your bolt in the barrel and slid it into position so you can attach a handle
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Unread postAuthor: knappengineering » Thu Jun 28, 2007 11:14 am

I already have a modded sprinkler valve that I want to continue to use so I don't want to build a new piston valve. So at this point I'm looking into using the bolt action technique.

@lukemc-If I use that design, do I put the magazine in front of the bolt so when I slide it forward it covers up the magazine and when i slide it back it opens the magazine and lets the ammo drop into the barrel?

Thanks for all the help guys! :D
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Unread postAuthor: lukemc » Thu Jun 28, 2007 11:44 am

yea i think i know what you saying just make it like this

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