richardbridges wrote:I don't mind wasting the bbs, but you are right, I want more power

In that case, this is the design for you:



Zero dead space, maximum efficiency and the highest velocity you're going to get for a given pressure.

What you created there is essentially similar to a spring piston air rifle - it would have been interesting to compare performance if the projectile was attached directly to the piston, eliminating the smaller barrel, or indeed to just have the smaller barrel using the same pressure and a convention...

I need to know what kind of numbers to reach or beat. you can easily add another barrel to increase ROF but why would you want to actually beat the ridiculously high numbers already achieved? BBMGs are wasteful enough of ammunition as it is, you're better off finding a way to make each shot more po...

I'll drink to that cheers!

yes yes, blame the parents... honestly, is there anyone left in the litigation loving US willing to take responsibility for their own actions?!

Waste of time really, all I got was vastly reduced energy in the projectiles. That's better than me, after a few shots of my prototype the barrel cracked and sailed off into the distance at an alarming rate of knots :roll: I tried this stuff not long ago under the exact same name: http://www.uksgc....

I don't think it will rupture at the sort of pressures used in typical pneumatics, as far as I know people usually use layers of aluminum foil for burst disks. Unless of course you score it with radial lines...

That is the right valve, you can use it as it is with electric actuation but with some slight modifications (replacing the solenoid with an outlet for a blowgun) you'll be able to get significantly better performance.

edit: here's how you go about modding it

at that price, certainly not. Buy a sprinkler valve and mod it

iknowmy3tables wrote:jack does a good job at explaining things and gives a lot of diagrams

Yeah, we got bored of testing the burst-disk pneumatic we improvised from cam-lock fittings at work and I have unlimited access to the internet from my desk

You've just described a nailgun :wink: The system is used on impact testing cannon to prevent the sabot from impacting the target and affecting the results of the test. The Russians also use a similar system in some cartridges like the SP-4 made for the PSS pistol in order to prevent propellant gass...

Hmmm, how is it vented?

Build the fuselage out of Soda bottles to give suitable compressed air tanks, have a barrel poking out the side with a small ball valve connected to a servo, chuck a bunch of BBs in with the air et voila, gunship!

The reloading can be done using a blow-forward breech that shouldn't be too hard to construct. However, some potential sticking points: 1) venting the chamber in between shots, you might need a chamber fan permanently blowing towards the barrel. 2) more critically, metering the exact amount of butan...

NeoSpud wrote:Not to be a nitpick, but QEVs like the one on mark's gun is a diaphragm valve.

Since some QEVs *are* co-axial piston valves and the piston/diaphragm valves operate on the same principle, I think all the evidence points to you in fact being a nitpick