SpudFiles

I'm about to order one of these 1/4" Bellpro QEV's for $35 aud posted, which is about as good as I can get without going ebay international.

Clicky.

After discussions with Carl he reckons the body should hold out at 300-400 psi. The main concern is the piston.

Basic question; will this hold up at around 300 psi?

And if not, does anyone know of a QEV available to Aussie gunners that will work well?

Barrel size it will be for is around 5mm.

Thanks guys

Edit: if it won't hold and there's no easily available QEV's I'll machine my own, I'd just rather order one seen as I want time over the holidays to work on it- school (and my access to a lathe for the time being) ends in 1 week..

Well, depends on the diaphragm material. The body will be plenty strong enough, but if the diaphragm is thin or made of a weak rubber, it could pop on you at those pressures.

I would go ahead and buy it, and if the diaphragm is too sickly for the task, I would just machine a piston, or a support for the old diaphragm.

Good luck.

Thanks. I'll wait for more responses, it'd be great if someone could chime in who has one of these (or similar).

If I can't find someone else who's used them at these pressures then I'll machine an integrated QEV/bolt action breech.

I'd say go for it, the body will be fine and the piston SHOULD hold up, just make a new one if the other one fails.

But I would want to "Pressure Test" it to slightly higher pressure than you would be running it at so that it doesnt turn into an unexpected burst disk valve

Dave

Bout to order it, $34 shipped.

I'll dismantle it before use and see what it looks like. I'll backfill any dead space with epoxy, and reinforce the piston if needed.

I already have a nice thick aluminum chamber turned, polished and knurled at the ends but I may make it a bit larger seen as it is so much larger than the barrel.

Then turn up a nice aluminum bolt action, make a bipod and I'm rolling.

Thanks everyone

Yea ive also been looking at getting a 1/2" Bellpro QEV and want to take it to 250-300 psi but im not sure how well the plastic shuttle cup/piston will hold up to the HP. Keep us posted on how it goes mate.

Sure thing! I'm ringing them tomorrow to ask if they'll do bank transfers, otherwise I have to wait for money to transfer from my bank to paypal, then order it. So it could be up to a week.

By nature, the 1/4" QEV would have less force exerted on it due to a lower surface area but it should show up if there's any problems with using it at 300.

I may yet get the 1/2" one, a few $ to go up from 1/4 to 1/2 isn't bad. Not like a 1/2" QEV porting to a 5mm barrel is overkill..

I'll keep ya posted

Mitchza89 has used a 1/2" Bellpro on a semi auto gun of his before but im not sure of the max pressures he used, heres the link;

http://www.spudfiles.com/forums/the-was ... 18036.html

I Messaged him a few weeks ago asking him about Bellpro QEV's, heres a quote from his PM,

"The Bellpro QEV's aren't too bad at all. I use 6-8mm bearings. Despite being a 1/2'' QEV, the sealing face that the piston sits on is about 8 or 9mm. Perfect for what I need but with a 12mm (1/2'') copper barrel, it's not too bad. A little constricted as you would expect but still good."

So i will be buying a 1/2" QEV and whacking it on a 6mm ID barrel for .22 pellets, should be some fun at 300 psi not Overkill just A LOT more fun lol

Off topic reply edited...

Cool, I might go for the 1/2" even though it would be less smooth than the 1/4" one. If only they did 3/8"

Ordered the 1/2" Bellpro QEV. He's getting back to me with an invoice for a money transfer.

The 1/4" may have been a slightly better idea. Less surface area to fail in..

But the 1/2" will give me moar barrel options, even up to .378.. And it's not like it would be impossible to reinforce