SpudFiles

Hey guys,

I've had the idea of making a BB piston valve rifle for a while now. It's all gonna be out of metal n I'm gonna mount a shock pump to it so it's like a pump action. With the specs I put into ggtd, I got over 1200fps at 150psi and over 2600fps at 400psi with a .12g plastic BB. At 1st I thought that it had to be so wrong it wasn't funny but I showed Chaos and showed Rna and it was right... I know that those plastic BB's are only very very light but geezz....thats really bloody quick.

For the idea I've had, im gonna reverse the chamber around so it acts like a stock and have a 6mm T coming out of the 10mm valve T that I can plug the schrader/pump into and attatch the blowgun.

I also thought of the idea (dunno if it's already been thought of) of using a quick release male-female fitting thats used on Compressor hoses and air tools to make a sliding breach but ehhh....I'll see how I go with getting everything else working first haha.

I'll add some pics when I get home. I did a rough drawing but I'll do a proper one on the comp when I get back.

Well thats quite impressive man. Go for it but there can be some problems reversing the chamber. Id just go with a simple over/under design or an inline or even coaxial. Id love to see this man

Proper air guns/rifles don't even fire that fast. If that is the right speed I'm sure the bb would quickly decelerate when it leaves the barrel. But nevertheless it would be sweet as if you build it.

Sounds sick Have fun going supersonic!

that is an awesome idea if it works 8)

GGDT tends to have some problems when it comes to calculating things involving higher pressures. You won't be getting super-sonic speeds using regular air, especially not Mach 2.

Those speeds sound insane! Even if it is 20-40% slower than GGDT anticipated, it will still shoot very fast.
Good luck in building it, and as always Im looking foward to seeing the finished product!

Yeah even if I get close to those speeds, because the bb weighs so little, its decelleration would be pretty intense. at 200psi which is what my limit is, I reckon it'll go around 800-900fps which I am def. happy with .

It wont go supersonic as your just dumping air with a valve (impossible to be supersonic). However it will be abel to get to 1000fps imo, with barrel tweaking and 200psi, you should use heavier BB's, theyre still so light i doubt it will really effect the fps @ 200psi, but would help accuracy / range / energy alot - have fun!

I'd say! Imagine being shot by that! (Not that you ever would of course) That would STING! Maybe even go into your skin....

Thanks alot for the advice Sniperjosh. I really appreciate it. Haha I can imagine it would hurt more then ya think

.12's will be horribly innacurate at that speed.

i reccomend at least .3 gram bb's. you will be more satisfied with their muzzle energy.

also, try searching mcmaster for some precision 6mm steel balls. they have a .0001 inch tolerance..... and are nice and shiny.

in fact, look in the stainless steel tubing section and you might be able to find 650mm of 6.01mm ID tubing, with a pressure rating if 100000 PSI.........

Have fun pumping it up with a shock pump. Jack pumped his small launcher to 400 and achieved about 1000 fps. That's more what you're looking at as far as performance goes. Make the chamber small if you are going to use the shock pump. 10 minutes between shots isn't fun.

Damn that would be great to get. I was gonna use 8mm copper pipe which has the same ID but its the soft kind that comes in big coils so I can imagine it would be as hard as hell to get perfectly straight... I might try and get some small fishing sinkers. I know I should be able to get some that are close to 6mm.

Hawkeye, I was gonna have a 25cmx15mm gal chamber. I want it as small as possible so the shock pump on it will be practical. I might even go 20mm....I'll see what works best

Hawkeye wrote:Have fun pumping it up with a shock pump. Jack pumped his small launcher to 400 and achieved about 1000 fps. That's more what you're looking at as far as performance goes. Make the chamber small if you are going to use the shock pump. 10 minutes between shots isn't fun.

The most I did was 1012 feet per second with a 0.12 gram airsoft BB, it's impressive for the sake of velocity but the effect on target isnt that dramatic - the low density BB loses velocity very quickly, and at those speeds tends to shatter as opposed to penetrating.

I had made a longer barreled version of that launcher with a larger chamber - the HVBB project which I detailed in this thread - unusually, while performance with lead pellets went up dramatically, the velocity with BBs actually went down, air is a funny thing

Edit: josh, it is possible to go just over supersonic by dumping air out of a valve - there are commercially available airguns like the AirForce Conder that can do so on a regular basis.