BTB sawed-off mark II

[al-xg]

I will, but I still haven't got a proper pilot valve. I've been using the small slide valve used to cut off the air supply when disconecting the bottle, but it only has a 1mm hole. I've reduced the pilot volume to under 8cm3 but it still dramatically reduces the power.
I'm using a small chamber volume (in spudgun standards) so its not meant to blow down doors. (Im aiming for 280J with 8g projectiles...)

But i'll stard my own post when i get it working properly.

[Brian the brain]

Good lord!!
58 bar?!?!?!




even I would be afraid to use that!


Imagine the damage!!

[al-xg]

Haven't you already ? Unregulated CO2 ? ok it wasn't in a piston set up but a QEV is like a regular steel fitting, its weak point being the polymer piston, and if that was to fail it would fire, but that risk already exists. So adding a safety ballvalve should do.

[Ragnarok]

Hmm, maybe if those pressures are possible, I will take HEAL to 35 bar instead when I'm done.

Hmm, potato with more power than a .357 magnum - now that would be awesome.

[CpTn_lAw]

that must be loud...even 500 psi is loud...now 850? man that's a lot of CO2 in there.

[Velocity]

...I got excited when I fired my copper rifle at 125 PSI ...I thought it was pretty loud too

[psycix]

Nice re-producable gun brian

Seems like your business is doing quite well isnt it?

[Brian the brain]

Too early to say..Let´s hope for the best.
In the mean while I´ve gone back to bouncing in the weekends to pay my bills.....

[Jack_Hogg]

What do you mean by the handle is excessive?


When the pump is removed the handle part empties up to the ballvalve.
The schrader is empty, no valve, just the outside.


Can't get a smaller pilot volume than this.
I built it like that on purpose.
Try 1/2" QEV, 1-1/4" chamber and 3/4 barrel.

It's going to be sold to guys that are used to .177 airguns...

They pay 200 euro's. Spudfilers would pay less offcourse.

So if your pump is removed, you close the ball valve, and then press the valve so that the pressure from the handle is released, and when you open the ball valve, will the piston still go backward? Is there enough space for air in the handle to trigger the piston to go backwards?

[LCTChamp]

Dus als je die pomp weghaald, sluit je de ball valve en dan druk je op het ventiel zodat de druk uit het handvat gaat, en als je de ball valve weer opend, gaat de zuiger alsnog achteruit? kan er dan wel genoeg lucht eruit om de zuiger naar achteren te laten bewegen?

English please! I don't know if you said anything important, but if you didn't you shouldn't post in a topic that is a year old.

[Carlman]

Dus als je die pomp weghaald, sluit je de ball valve en dan druk je op het ventiel zodat de druk uit het handvat gaat, en als je de ball valve weer opend, gaat de zuiger alsnog achteruit? kan er dan wel genoeg lucht eruit om de zuiger naar achteren te laten bewegen?

oh for christs sake!! kicking a topic is one thing but doing it in another language is another!

"So if you pump weghaald, close the ball valve and then press the valve so that the pressure from the handle is and when the ball valve again opened, the piston still backward? can make sure enough air out to the plunger to move backwards"

[jonnyboy]

And whats funny almost all his other posts are English...

[jrrdw]

I don't think it's funny at all.

Go back and translate this to english or I will delete it, you have one day to do it, also your kicking up old topics which can be against forum rules. I know you can use english I suggest you use it.

Go read the forum rules!

[Brian the brain]

This should have been PM'ed.

He wants to know how I fill it and if the balvalve is big enough to function as a pilot.

It fills from the handle side.When full the ballvalve is closed.Pump is removed and yes..the ballvalve is very capable of piloting the QEV.


Next time PM me.
Then nobody flames you for speaking Dutch either.


Vinden ze niet leuk...
To all others...
This topic is so old, just pm me if you have any questions.No need to bump it anymore.