QEV + Pop-off = Full auto?

[PVC Arsenal 17]

A looong time ago when I joined this site I found this. (man I didn't know jack sh*t back them!)

Of course since I'm notorious for not completing projects, the gun I was working on and posted about in that thread has yet to be completed.

My question stands: How can you achieve full auto using a piston valve (or QEV), a pop-off valve, and a constant air supply?

Apparently Saladtossser did it, so I know it's possible. But what is necessary for it to work? A certain pilot volume? A certain air supply volume? Specific pressure?

I would think that as soon as the pop-off vents, the air supply would refill the pilot volume and in turn prevent the piston from moving back all the way. Or the constant air supply would be too great and hold the pop-off open. Yet we saw it work!

There must be some compromise between pilot volume, supply volume, running pressure (which would mean pop-off's with different ratings).

Saladtossser also mentioned that in order to achieve full-auto he had to pull the pop-off ring ever so slightly. I'm guessing that what this did was relieve some of the spring pressure so the valve could vent easier. If thats the case, then a lower running pressure should solve that problem.]

Anybody have some ideas?? JSR??

[JDP12]

umm maybe look at this

http://www.spudfiles.com/forums/full-au ... t4108.html

[PVC Arsenal 17]

Bah damnit!

[jackssmirkingrevenge]

umm maybe look at this - full auto marble gun

beat me to it

I had sketched up a similar idea for use with my blow forward bolt but never actually got round to making it:

[psycix]

What the heck is that "blow forward unit" dont you just mean a 90' elbow?

[jackssmirkingrevenge]

What the heck is that "blow forward unit" dont you just mean a 90' elbow?

blow forward unit

[Hotwired]

T'is a blow forward bolt to seal off the ammo feed while still letting the air blast through.