Do a video of you firing it 300 ft deep and then breathing from the same tank

congratulations, you should be proud of it. It would be cool If you could make one with a magazine so you don't have to put a pellet into the breech every time.

In my opinion, your best option is to buy a floor bike pump, and make large-ish chamber out of steel or aluminium pipe and either attach it to your gun, or put it in a backpack and run a line to your gun. I have gone down the co2 route before and I implore you not to.

Maybe you could use a copper barrel and solder it in...

It's going to cost you a lot of money to run a cloud off of small co2 canisters. You will get around 3 seconds of firing out of each canister. Even if cost is no issue, it will be annoying having to change canisters all the time.

I can't wait to see it in action. It looks great. Have you given much thought to how the cartridges will eject? (Side ejection/magazine feeding) Is the sheer force enough without anything guiding the motion?

I've looked around but information on the gas mags is pretty sparse. I'm pretty sure it would be a spring loaded 2 way spool valve though.

http://www.wisc-online.com/objects/View ... ID=HYP4807

Ah, I see. Thank you, i have heard about differences in pressure on cold dats, but that's large.

@jsr laugh at me all you want, you're just showing my talent is over your head.
:withstupid:

An airsoft mag usually looks like this. http://i894.photobucket.com/albums/ac142/lozz08/100110_004326.png The green is liquid propane. A hammer hits the purple button, which opens the valve (yellow) for a shot. You could use a schrader where the yellow is. You could fill the chamber to say 400 psi w...

Duh guys, it was clearly a money making machine jeez, read between the lines.

I don't see any benefit to you using a hammer valve for now... put a pressure gauge on the small chamber and make only a small hole between the two chambers so that you can control what pressure you will fire at. Fill the main chamber to as high a pressure as you can, and use the ball valve to fill ...

A problem for you is going to be power consistency. With a chamber of compressed air without a regulator, each shot will get weaker as the chamber empties. If you dont know how far a shot is going to go, it can be hard to aim it.

Your description sounds like it won't actually give you semi auto, because you have to refill the smaller chamber after every shot. As long as you understand and accept that, the design will meet your expectations. I would suggest the following; Purchase a quick exhaust valve. Pick a size that match...

If it is too glossy after that coat use 1000 grit sandpaper. For a coat with superior thickness and durability I use marine epoxy with pigment. It can iron out imperfections in the construction too

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Ah, loveley, with this information i can fuss around so much less... I can't believe i overlooked using solder for so long... thanks guys.