First Project - Semi-Auto

Show us your pneumatic spud gun! Discuss pneumatic (compressed gas) powered potato guns and related accessories. Valve types, actuation, pipe, materials, fittings, compressors, safety, gas choices, and more.
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tetra
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Sat Feb 28, 2015 7:20 am

So this is my first Semi-Auto Pneumatic rifle, I have made Single Shot cannons in the past but I wanted to really reach out with this one. I had a idea for a system but I can't figure out how to do this mechanically without two triggers the first to load the ammo by air pushing a piston into the ammo from a spring loaded magazine past a hinged flap (spring loaded closed?) then a spring retracts the piston. There will probably be a magnet or divet for the loaded ammo to rest in. The Second trigger shoots the loaded ammo pushing directly on top of the hinge to make sure it stays closed. Any feedback or ideas are appreciated. Also excuse the bad handwriting an expo marker plus spending all night working on this idea mixed with horrible handwriting to start with ends up like this.
Air-Bolt-Schem.jpg
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jrrdw
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Sat Feb 28, 2015 4:26 pm

You know about gas tubes?

Welcome to Spudfiles.
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tetra
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Sat Feb 28, 2015 5:02 pm

Not offhand, if you start explaining it I might have an idea but off the top of my head not a clue. And thanks for the welcome.
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jackssmirkingrevenge
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Sun Mar 01, 2015 8:06 am

Don't you think a blow forward valve would be a better idea?

[youtube][/youtube]

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hectmarr wrote:You have to make many weapons, because this field is long and short life
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tetra
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Sun Mar 01, 2015 9:57 pm

@jack The blow forward in the video double feeds at the end that worries me and the ammunition I am going to be using is CO2 cartridges cut off and weighted with lead either 1-1/2" or 2" long. And I had no idea what kind of Anything to use, this is all new to me and the idea for the drawing popped into my head, though the picture I put on the post is the third revision.
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Sun Mar 01, 2015 11:19 pm

Watch the animation long enough you'll figure it out...
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tetra
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Sun Mar 01, 2015 11:36 pm

@jrrdw The animation jack posted?
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Mon Mar 02, 2015 10:37 am

Yup, that's the one. :bigsmurf:
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tetra
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Mon Mar 02, 2015 5:02 pm

It looks like I will have to make it pretty large to fit my ammunition.
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tetra
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Tue Mar 03, 2015 1:37 am

Is that what what wyz2285 did here http://www.spudfiles.com/how-to-databas ... 24574.html? It look a little different mainly the air is coming from the side hold not through the bolt.
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tetra
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Wed Mar 04, 2015 1:26 am

Okay so I have been reading more on the Forum and have come up with this thanks to wyz2285 for his tutorial for a .50cal semi-auto http://www.spudfiles.com/how-to-databas ... 24574.html. This time I actually used pneumatic system symbols. Oh and the magazine will be from the bottom not the top.
Air-Bolt-Schem-v2.jpg
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Thu Mar 05, 2015 11:31 am

If this is your first project, Tetra, I'd really suggest going with a hammer valve system first. The performance/efficiency might be low, but it'll teach you a lot more about how compressed gasses function. Plus, the materials will be a lot cheaper than the QEV system.

However, if you're set on using the QEV system, I'd recommend going with JSR's 20$ QEV semi auto system.
http://www.spudfiles.com/how-to-databas ... 23626.html
If you still need the cycling bolt, just combine the blow-forward valve. Should work just fine and cycle the ammo quite well, without getting overly complex or expensive.
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tetra
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Thu Mar 05, 2015 7:58 pm

Well I had already ordered most of my parts so I guess I get to work through the challenge.
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