SpudFiles

Well, as promised, i built a .22 caliber semi auto rifle using a QEV and slide valve.
It's not fully finished-I'll put a scope on it at some point and i need to make either a bolt or blow forwrd bolt for true semi-auto
Specifications:
-Chamber is 22mm copper chaped into a stock with fittings.
-The pilot chamber is again just 22mm copper.
-Main valve is a 1/4 QEV with a 3/8 exhaust (I have 6 of them )
-The pilot is a 1/4 Slide valve from eBay.
-Barrel is 5.6mm aluminium sleeved in 15mm copper, perfect for .22 pellets.

That's about it really, i've tested it at only 150psi so far and i get about 4 or 5 good shots with pellets before the power drops.
The accuracy isn't great either as my sights are just glued on and are way off.
I'll post a shooting video with some damage on Youtube later but here are some pictures and a quick video dry-fireing at 150 psi.









I need to get a good track pump as it takes a good 5 minutes to get to 150 psi with a shock pump.

Enjoy.

Very cool Is the trigger difficult to pull? My was when I tried to put a spring on it so it closes automatically...

i gotta gets me one of them slide valves
nice build.. i like the shape of it.

Thanks, the trigger is quite hard to pull but i don't mind, It needs to be quite tough for the slide to return fast enough and avoid air loss.

I like it. Portable.

Mhm, it is Suprisingly light too. I might make a blow-forward bolt today for BBs as with pellets the performance isn't that great because of the small chamber and low pressures.

hows the velocity?

beastmode986 wrote:hows the velocity?

From my own experiments with a similar setup:

In response to some questions about the sort of power available to this setup, I hooked up a 12 inch 6mm barrel and did some chrony testing at 120 psi. The firing chamber volume is around 3.5 cubic inches, a little wasteful but that's what I had

Using 0.25g airsoft BBs, I got an average velocity of 590 fps, more than enough to punch through a soup tin. With some adapted 1 gram 0.22" pellets I got an average of 355 feet per second, fairly decent.

As always, for small bores you need higher pressures than what your average compressor can put out for decent (adult airgun range) power.

Also, qwerty, shouldn't your sig be "a dyslexic man walks into a bra"?

Also, qwerty, shouldn't your sig be "a dyslexic man walks into a bra"?

I pondered on this for a while... Surely dyslexic people would be able to read the letters in the right order but not be able to spell them?
I honestly don't know as i'm not dyslexic