35 bar repeater ( new pics on page 4)

[Brian the brain]

You want pictures??

This thing is far from finished, but I'm making progress.
I cut up a blowgun so far it is now only a hammer valve.
This valve works even better than the ones I tried to make myself.


I used the paintballtank as the reservoir to get a decent number of shots.
I got about 7 good ones.
With the short barrel it was pretty powerful, but ofcourse one twice the length would give better results.
Pressure used is 30 bar.
First shot was the aluminium plate, wich was set up loosly on my bench.
It flew off.
Second was at the old "body"I made for it, wich doen't fit it's current shape.The body's only function was to try the hammer.Again not clamped down.This too took off-------------------------->pachooooh

third and fourth shot are not shown.Went trough 3/4 inch of laminated fournature board.Exit hole was 2" ( yes, that is rediculous)

Oh..and it might be worth to mention, the QEV fires full auto with a pop-off pilot.
I'll get back to that sometime in the future, but this repeater is too much fun right now.
Full auto uses A LOT of air, I can tell you that much! and it made my ears ring..
On to the pictures.

[MaxuS the 2nd]

Ooooh, very nice BTB, but what's with the random Tee in the chamber setup?

[Brian the brain]

Didn't have the right fitting..

It's just a prototype, I haven;t bought anything for it.You can tell it's a piece of cr*p can't you?

When I get a day off I'll build it properly, with a 1 1/2 fixed reservoir and proper fittings to connect it all.

I'm contemplating building the lever out of plywood.
I've tried aluminium, it takes too long to jigsaw..


What do you guys think so far?
repeating sawed off is in reach ( or marble cannon)

[MaxuS the 2nd]

Actually I think it's pretty damn cool. Thinking of a magazine feed?

[Brian the brain]

Lever action.I want the magtube parallel ( sp?) to the barrel.

I want to make this thing look it's best ( in case we have another competition, )
Hardwood stock etc.

I guess a lot of people will be turning their QEV's into repeaters from now on.
Trick is a very small ( 1.5 mm) equalising hole in the side of the piston and a soft spring behind it.

regular blowgun and large reservoir will work.

[MaxuS the 2nd]

Do the high pressure, but small volume shots still give a good amount of power?

I have something up my sleeve if we have another competition.

[Brian the brain]

Normally, when the projectile leaves the barrel, the rest of the gas is wasted.Now the QEV reseats very fast.
So fast in fact you can't see the piston move when you fire it.
Still a pretty big boom though...
And you can see by the damage it's no joke.
The barrel is about 40 cm long.
With the correct reservoir and pressure,
1 meter should bury 5 shots into solid wood, at least

[Hotwired]

I guess a lot of people will be turning their QEV's into repeaters from now on.

My cannon's been a 5-6 shot 28 bar QEV repeater for over a year now

Forcing the QEV to act in the same way as a sprinkler valve is a interesting variation though, allows a simpler way to have a continuous air feed.

[Lentamentalisk]

ok, sorry to kick this up, but I was wondering how one would adjust the power on it, how much air is released per shot. Would that just be done by adjusting the strength of the spring in your blow gun, or the strength of the spring in your QEV, or what?
Also, how does the dropping pressure effect how quick it resets?

Edit: did I understand you correctly it that, by adding a spring, you can fill the cannon from the chamber side? Is that only if you drill an equalization hole? If so, how strong of a spring is needed?

[POLAND_SPUD]

yeah I think there has to be an equalization hole... normally the piston on QEVs works as a one-way valve

[Brian the brain]

NEW PICS !!!


Yep.You need the eq-hole.
Can't call it kicking up when the topic is alive and well now can you?


Power is determined by the hammer.The force behind it and more importantly, the momentum it has.
The longer the exhaust valve stays open, the longer the qev does too.

The spring behind the piston is the SAME spring that returns the hammer valve and it is very light.Resetting is instantly, therefore the hammer is the most important factor.

I have finished the working parts in the grip, I gave it a quick paintjob to show it to you guys.I will resand some parts of it and give it an even smoother finish.
Handle is geniune hardwood, handcarved to fit my hand exactly.

The trigger is aluminium, the hammer is brass.Action is very smooth ( like a top notch airgun) and when fired at 20 bar this thing is incredibly loud...
I've decided a lever would destroy it;s looks, so I'm going for my favorite, breakbarrel design.

Not that much more work to do...just buy the reservoir bits and build the "basculating"part wich holds and rotates the barrel.

Remember this is a very powerful, multishot gun...and I still need to smoothen all the bodywork
Here are some teasers:

( and don't forget to comment!!)

[FordGtMan]

Wow, that handle looks sweet. Looks comfy too..

[Brian the brain]

It's comfy alright!
It's even the correct angle.With my arm hanging down ( relaxed) the gun is pointing straight down.

This is a requirement for powertools..so it cant hurt if you incorporate that into a gun design...

My wife can't hold it, as it is a perfect fit for my hand...

[MaxuS the 2nd]

I'd take my hat off to you BTB, that is if I could find it.

[Lentamentalisk]

That is F***ing awesome! Are you still planning on an "ammo elevator" reloading system? or what is this favorite break barrel method?

Also, how are you planning on integrating the air system? Is it going to go under the barrel, or will you have some sort of CO₂ tank attached?

Awesome idea: If you filled one specially shaped chamber with liquid CO₂ from a big tank, and then regulated it off of that into your firing chamber. That way you wouldn't have to deal with an odd, bad looking CO₂ tank hanging off.