Thanks for your help, I'll post pictures of the finished cannon when I'm done.

I took the valve apart again, and there is a tear in one o-ring. Any ideas where I could get replacements?

It leaks at any pressure, even 1 atm. I didn't see any tears in the o-rings, but it did seem to slide really easily. Also, the o-rings weren't the typical black rubber, but seemed more like a tan latex material.

Yeah that was the first thing I did. It leaks out where the slide meets the inner cylinder on both ends, past the o rings.

I recently purchased a qev and slide check valve for use on a semi-auto. The qev works fine, but the slide check valve leaks when under pressure in either position. I tried lubricating it and inspecting the o-rings, but I can't figure out what's not working with it. I bought it new, and it looks exa...

airheadnoob wrote:btw jsr no feet
the only thing i could complain about that the connecter where the barrel goes its a 4/8 " instead of a 1/2" :X
very satisfied with bellpro

As far as I know, 4/8 equals 1/2, unless I don't understand something here.

Never bring A knife to a gunfight.
[youtube][/youtube]
However, bringing several knives is perfectly fine.

Video embedded by jrrdw.

Come on guys. I don't like the way it's set up either, but some good does come of nerf modding. Most of it is just 8 year olds that lied about their age, but if you look at some of the members' posts they're as good as any on here. Also, the goal of nerf modding is different. Here you're trying to p...

Okay, It's QEV time then. I think I finally have all the aspects of this gun figured out, with your help of course.

You posted while I was editing, heehee! If I used a valve with a threaded exhaust, could I use that to fire the projectile without a QEV, or is that kind of valve too slow?

I'll still need a QEV right? If I used a 3 way 3 port valve (normally open) could I just use the exhaust to fire the gun? And are the ports npt on the MJVO-3?

Well, I think I found a piston on Mcmaster. It has a stroke lenght of 2", which will be enough since this will fire 1.5" nerf darts. Oh and screw the sleeve valve and QEV idea. I was going to do that until I clicked your links. These seem cheaper and more efficient. EDIT: I will still need a QEV wit...

If I understand right, I would want a 3 way 3 port valve, but all the valves matching that description are 10-32. Does mcmaster have adapters to npt?

Thanks again everybody. I think I'll probably go with one of those slide check valves, considering I couldn't find spool valves anywhere. I've decided against the blow forward breach in favor of an air cylinder actuated breach. Any good sources for air cylinders? Mcmaster part number is preferred, s...

Okay, thanks for all the help everybody.