First cannon ruffly 40cal/10mm

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.
HalfBaked
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Fri Jun 20, 2014 12:50 pm

This is my first really successful build. Tried a couple others that didn't work. So here we go this is a breach loading blow through bolt design I came up with while walking around the hardware store.
Here's the parts list:
1- 1/2 x 6 inch brass nipple
8- 5/8 x 1/2 x 1/2 inch nylon spacers
1- 1/8 inch x close nipple
1- 1/2 inch cap
1- 3 foot x 1/2 inch round aluminium tube
1- 8-32 x 1.5 inch screw
1-1/2 fmp x 3/8 fmp coupler
1- 3/8 inch x close nipple
Started with the 1/2" x 6" nipple cut the breach and the "L" for the bolt handle. I had decided to make the bolt 3" long and cut the "L" so the bolt would clear the breach enough to load. Next I inserted the spacers into the nipple 3 at the front and 5 at the back. I used the 1/8" nipple in the end of the breach to seat the breach and the projectile so it was not just two ends of tube butted together inside a spacer. The nipple actually threaded its self into the bolt tube nicely and the 8-32 screw was drilled, taped and run in so it went through the bolt wall and the nipple. Filed down the thread on the exposed portion of the 1/8 nipple so it would go in to the barrel with out catching. I drilled a 0.5" hole through the cap and screwed it down over the front spacers,had to widen the hole slightly to allow the barrel to pass through and used jb weld to seal the gap between the barrel and the cap and lock the barrel in place.
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Then I attached it to a q.e.v.( ment to get one with 1/2" ports all round but didn't read well and got one with two 1/2" ports and a 3/8") using the 1/2 x 3/8 coupler and the 3/8 nipple.
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I am using an old 9 oz. paintball tank as the firing purge tank, it has a wonderful 3/8 pipe thread I can connect it to the q.e.v. with just a couple fittings(need another 3/8 x close nipple to attach it. To fire I intend to use a compressor hand held blower valve.
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Waiting for the main tank to arrive so I can complete construction. I did however test it to make sure it worked, which it did better then expected. Here is the test/ prototype rig.
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And here is the projectiles the I tested with and was inspired to build this for, though I am going to construct some custom projectiles for it eventually.
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Any thoughs or suggestions are welcome.
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jackssmirkingrevenge
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Sat Jun 21, 2014 9:52 am

Not bad at all!

You should really consider a three-way valve as a pilot, much more efficient in terms of air use and more powerful due to quicker piloting.
hectmarr wrote:You have to make many weapons, because this field is long and short life
HalfBaked
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Sun Jun 22, 2014 7:40 pm

jackssmirkingrevenge wrote:Not bad at all!

You should really consider a three-way valve as a pilot, much more efficient in terms of air use and more powerful due to quicker piloting.
Will have to look in to that, for now though I just use a ball valve to prime it then close the valve and fire with the blower. Also had to scrap the paintball tank idea as the thread in it was not compatible with the fittings I have, it is a 3/8 tread but the connector won't screw into the tank. So I have decided to use a 3.3 oz. (90 gram) cartridge which will work with the fittings I have.
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