SpudFiles

OK,
So the paintball tank, adjustable regulator, adapter & pump arrived. I also got another QEV & Slide vavle.
I removed 2 shims from the regulator to get about 550 PSI of output pressure.
It took me about 20 minutes (with 1 minute brakes every 5 minutes) to pump the 48/3000 tank to 3000 PSI.

I'm gonna improve the rifle i made and make a new one.
For the existing rifle I intend to replace the shredder valve with a quick disconnect and add a pressure gauge.
I wanna try and make the new rifle a s lightweight as possible: a 10mm 25" long aluminum blowgun as barrel, a 100cc air chamber (steel pipe) , a QEV, a slide valve, a quick disconnect & a gauge.After building this gun as clean a possible, i intend to embed everything in a wooden stock. A 2.5-10X40 scope will be mounted. The rifle will then be connected by a remote line to the paintball tank, which will be in a backpack

Both rifles will be working at 550 PSI.
GGDT data:

It took me about 20 minutes (with 1 minute brakes every 5 minutes) to pump the 48/3000 tank to 3000 PSI.

So much better to do useful exercise rather than mindless lifting in a gym

Those are some pretty healthy numbers, good luck with the build!

Don't forget that the remote line counts as dead space, the longer it is the less shots per tank you will get.

So much better to do useful exercise rather than mindless lifting in a gym

My thought exactly, I told my girlfriend she can now skip spinning class & pump my tank instead (sounded weird & she didn't like the idea.. )

I'm having a bit of a dilemma regarding the breech loading design. so far i just drilled a hole in the barrel and used a rubber gas tube to cover it as a sleeve, the rubber tube can move forward\backward with some lube on the barrel. it works fine, but I'm thinking of inserting a small piece of a 10mm outer diameter aluminum tube into the barrel, than use a screw to help it move. I know for sure it will be more comfortable to load but i'm not sure how good will it seal

I told my girlfriend she can now skip spinning class & pump my tank instead

Excellent phrasing

I know for sure it will be more comfortable to load but i'm not sure how good will it seal

Without o-rings you'll lose a bit of power through leaks for sure.

I love the idea of a piece of hose as the sleeve for your breech! Maybe it just needs a handle.

Like this ?

Like this ?

yes, only with a rubber sleeve instead of metal.

so, i just started testing today & i got a problem. I've connected the paintball tank with the remote line to the slide valve+ qev, like this:


it's the exact same setup as the first rifle only instead of the soda stream tank i got the paintball tank with the regulator.

when i open the regulator and take a shot, the slide valve won't go all the way backward (creating a leak), i think the pressure is to great for the slide valve to move all the way backwards. when i close the regulator & stop the air, it's easy to move the slide valve.

I've noticed on vng21092 .177 QEV+Slide Valve post that his paintball tank is connected to the air port, not to the pilot port & the slide valve operates fine at 800 PSI. is that the solution?

vng21092 .177 QEV+Slide:

Increasing the pressure should make the slide valve harder to open (more force on the o-rings -> greater expansion -> more friction) but it shouldn't limit its range of motion.

his paintball tank is connected to the air port, not to the pilot port & the slide valve operates fine at 800 PSI. is that the solution?

The beauty of the slide valve is that it is a three-way valve, simultaneously piloting the valve while also closing off flow from the main chamber. Note that in the example you posted, there is a separate ball valve that you need to open to fill the chamber before every shot, and then close before firing to avoid emptying the whole tank.

Note that in the example you posted, there is a separate ball valve that you need to open to fill the chamber before every shot, and then close before firing to avoid emptying the whole tank.

yeah, that's why i rather go with filling the air from the pilot side as I did before, but i have to find a way to deal with that slide valve. maybe I'll build a button valve similar to the one here

Thanks for all your help JSR!

Here's a way to go about it, needs some fabrication but basically you would need to cock the slide check forward against a spring and lock it with a trigger. When you pull the trigger, the spring moves the slide quickly, giving you better piloting time and less air lost in the transitional point between airflow directions.

Thanks for all your help JSR!

Pleasure

I removed on more shim from the regulator & now the slide valve is moving smoothly. got a different problem now (it seems like a never ending project, but i like it): the PCP pump stopped working, i guess i was pumping it to fast and one of the O-rings went bad.. I'll rebuild it this weekend (came with a rebuild kit) .

I did build a wooden stock for the 15.5mm rifle (came out nice) and planning to build one for the 10mm one when it's done.

I'll keep you posted

Good news! I managed to fix the pump, one of the O-rings was damaged, i guess it came this way from the factory, but what can you expect from a 70$ chinese pump it works fine now & i got an extra o-rings kit.
here is the stock i made for the old 15.5mm condor style rifle, it's not finished yet.. still got some sanding & shaping to do, but i'm getting there. after that i'll mount the 3-9X40 scope on it.

ones that's finished I'll get to the new 10mm rifle with the 2.5-10x40 scope, it will have a smaller, 3\8" QEV + Slide valve to avoid barrel potentially choking & i hope i can embed it all in a new stock so the valves will stay hidden.

JSR, you gave me lots of inspiration, you should come & shoot it!

what can you expect from a 70$ chinese pump

Porting drilled in Chineseium is notoriously difficult to deburr

to avoid barrel potentially choking

This isn't really an issue per se, GGDT tells you this to say that you can have a bigger barrel if you want. That being said, with a smaller QEV you'll get more efficiency.

here is the stock

Nice!

JSR, you gave me lots of inspiration, you should come & shoot it!

Good luck bringing me back to Europe but I'll be sure to let you know if I'm in the area

Peace among worlds!

Ok, I'm all finished with the 15.5 mm rifle now. I used some silicone grease on the slide valve, cleaned the barrel, mounted a scope and Voilà - it's beautiful!
I did some shooting - 10 meters away the 54 grains nail darts went thourgh 3\4" plywood like butter and got stuck in the wall behind it. accuracy really improved, i guess the consistency in pressure helps

I wonder how many shots can i get from the 48/3000 paintball tank. I'll have to make some more darts & check.

can't wait to build the 10mm one (allready got 63 grains bearings balls for it) , I think i'll make the air chamber half the size (50cc) this time, GGDT tells me that velocity won't be affected much by it (gotta get a chronograph), and i suspect it will increase (double ) the amount of shots .


I used to spend a lot of time with guitars & amps (building, playing, modding ).Now, spudguns are my new favorite thin :bom: !

I just shot it again and I've noticed it's really loud ( i had loud music on when i shot it before).. is that a bad sign? like barrel too short ext..?


thinking of making a silencer for it.