SpudFiles

Well I am thinking about building a gun that is semi-auto but I am not sure what valve would work best all the guns I have seen that are semi-auto just look like they have a modded sprinkler valve am I wrong or is it just a modded sprinkler valve?

Thanks for any help

Sounds like from your position, the best option for building a semiauto gun would be to simply build a normal cannon and then hooking it up to a CO2 regulating system so you would refill the gun instead of controlling the air. Another possibility (one of which I have never tested) is using BCArm's semi-auto pneumatic cannon: a tutorial seen here.

thanks you gave me a whole new idea and it will be just as good thanks again

You CAN make a semi-auto w/ a sprinkler valve. But you'll have to wait until the sprinkler reaches equilibrium on both sides of the diaphram.

Or just have a blowgun valve.

I would use a modded sprinkler valve with a blow nozzle mounted straight into the cap on the sprinkler valve. I would also mount a regulator on it so you could us a CO2 tank in a belt pouch and a remote line. Then you can just fire, wait a few seconds for it to pressurize, then fire again. Then all you need is to figure out the breech loading system.

so a sprinkler valve wouldn't decompress the whole tank????

No. The regulator would allow the air from the CO2 tank to slowly fill the air chamber to the desired pressure. Once the air pressure above and below the diaphram in the sprinkler valve equalized at the desired pressure the regulator would shut off the air flow from the CO2 tank. The gun would then be ready to fire. Once you fire the gun and the pressure is released then the regulator would again allow air to pressurize the system as before.

ok thanks im going to use a 5 gallon air tank on my back

What??lol. Are you kidding?? A HPA tank or CO2 tank used for paintball would be much more practical.

ya but I dont want to keep going to a store and paying $3.50 for every fill

Those tanks last a very long time...

Also if you do intend to shoot paintballs, A paintball tank would be much more practical. Especially given the low volume of air you'll be using in the gun. Even using the small 12g cartriges you'd get a few shots with each before running out of air.

ya but I dont want to keep going to a store and paying $3.50 for every fill

When I read that I almost fell off my chair. I pay $2.70 for the gas for a single shot. Seriously, paintball CO2 tanks would last forever on this thing, and if you have 2 of them, you'd never be without a gas source. I wish I had that luxury...

Well I might do that but Im not going to shoot paintballs I will be shooting tennis balls but I will really rethink what I am doing now thanks for all the help
and

When I read that I almost fell off my chair. I pay $2.70 for the gas for a single shot. Seriously, paintball CO2 tanks would last forever on this thing, and if you have 2 of them, you'd never be without a gas source. I wish I had that luxury

I have 4 tanks 2 20oz. tanks 1 16oz. tank and 1 9oz. tank
(I use to paintball alot) 1 more reason Im rethinking this whole thing