air is air... you don't get free air from having a single chamber...
if you want to get 10 - 20 shots from one tank it has to hold 10 - 20 times amount of air for each shot... I see where you're going here... 'that tank isn't big enough so I'll get a HPA setup that will fill it while the gun is firing'
That will work but it makes little sense in reality.... think of it a bigaxx tank plus a HPA setup...
wouldn't a small 100cubic cm chamber and a HPA setup be better?
think of it... 100ccm chamber X 18 bar = 1.8 L of air at atmospheric pressure
flow of most 1/8" 3 way valves is ~300 l/m @ 6 bar -> 5L/s at 6 bar
I moddeled this example in fluidsim and it seems that you could achieve 5 RPS with a setup like that (100ml chamber 300l/m flow and at 18 bar)
ok here is something I wanted to show you....
have a look at this valve http://www.boschrexroth.com/pneumatics- ... eID=p31067
The valve can be used as the main valve and since it is a 3 way you won't need a separate 3 way to turn this into a semi/fullauto gun...
I am guessing that its flow is good enough for 9 - 10mm ammo
Now the best part... you can also buy this one http://www.boschrexroth.com/pneumatics- ... eID=p31131
it's a 5/2 valve so you can have two guns in one gun
(in case you don't get it... attach barrels to both exhausts and chambers to ports A and B... air source is connected to port P... when the valve is in one position chamber A is filled while B is exhausted... when the valve switches to the other position air from A is sent to the barrel at ex. A while chamebr B is filled.... clever huh ?
anyway I just wanted to show that you can use some DCVs as the main valves...