jonesy42's Qev (crossbow) rifle build

[jonesy42]

Hi guys.... I am going to use this (chinese made) full - moulded crossbow stock, for my
Qev rifle build.
I want it to be semi - auto, (muzzleloading for now is okay).

I will be using the following: 1/2 inch 250psi qev , parker 3 way trigger valve, ninja slp 300psi regulator, a 3000psi "spare air" scuba "buddy bottle"... No firing chamber made as of yet.

If you look at the pics below, i was thinking of having the main air tank joined straight out the back of the qev where it is (roughly) sitting in the pic now, but raised a little so the air bottle can sit on the top of the (rifle butt) and fasten it there?... Which in turn would allow space for the firing chamber to run under the fore-stock...,,Ive heard of better performance if mounted directly behind the pilot too, instead of going through a elbow or similar, but not sure if it matters or not?
Although mounted in this way, it would prevent me using open sights or a scope by sitting
up too high and getting in the way when the barrel is on.... Even though the "spare air" scuba bottle is quite small and light, Its roughly 400mm x 70mm.... Its at my work at the moment, so i don't have a pic of it. I will post a photo of it tomorrow.

Considering i am nOOb, any diagrams/suggestions on mounting configurations, firing chambers, remote lines, fittings etc, i could go with in my build would be greatly apreciated and considerd.

Thanks a lot spudders!

PS:, The "inner" barrel is going to be 650mm x 6.03mm in diameter

[sagthegreat]

really nice i like it

[8tonsemi]

That is awesome, I haven't seen anything on the forum like it. Good job

[jonesy42]

Thanks fellars,... I want to do it right the first time and not "half-arsed" if you know what i mean.

[Gippeto]

I will be using the following: 1/2 inch 250psi qev , parker 3 way trigger valve, ninja slp 300psi regulator, a 3000psi "spare air" scuba "buddy bottle... No firing chamber made as of yet.

Safe to assume that you have tried the regulator in that tank? Wondering if the threads match up?

If you look at the pics below, i was thinking of having the main air tank joined straight out the back of the qev where it is (roughly) sitting in the pic now, but raised a little so the air bottle can sit on the top of the (rifle butt) and fasten it there?... Which in turn would allow space for the firing chamber to run under the fore-stock...,,Ive heard of better performance if mounted directly behind the pilot too, instead of going through a elbow or similar?

Although mounted in this way, it could also prevent me lining up open sights or scope by getting in the way when the barrel is on?....


The air used for the shot will be coming from the firing chamber attached to the side of the qev and not the bottle...having the bottle positioned behind the pilot offers no benefit and will lead to the high mounted sights(and subsequent rifle cant) issues that you mention.

Even though the "spare air" scuba bottle is quite small and light, Its roughly 400mm x 70mm.... Its at my work at the moment, so i don't have a pic of it. I will post a photo of it tomorrow.

Aside...MGD is an acceptable substitute for Sleemans Honey Brown...if in a pinch.

[jonesy42]

@gippeto,.. yeah the thread on my scuba bottle is 3/8, what if i mount it under
the fore stock, i think it would fit nice there?

[Gippeto]

Bottle threads on the regulator will be 5/8-18UNF. Outlet thread is 1/2-14NPS BTW.

Under the forestock is a better position IMO....if it's thin enough, a cutout in the butt stock perhaps? Largely dependent on how you prefer a rifle to balance. My preference is to have the balance forward on a bench rifle, and rearward if shoulder fired.

[jonesy42]

yeah, i meant to say 5/8 had a nOOb moment.

Ive, also got one of those rectangular black qev's that wyzz
done the video on, are they okay for 300psi?
probably fit in better and sit a little lower than the alpha qev

[Gippeto]

To quote the popular..."How long is a piece of string?"

Make and model of the qev you have at hand will go a long way toward determining such things.

Then try googling for the spec sheet...and post it up.

[jonesy42]

Hey guys,...If someone could could do me a big favour and convert the specs for this project
on ggdp,... eg: firing chamber recomended size, and what fps it will approximatly be
shooting at with the finished product it would be very much apreciated.... I would do it myself but its hard when your using, (my laptop died) a sony ps3 to post/upload photos lol, and it won't download the program anyway.
These things (sony ps3) have crap web browsers etc in them. The photos you see were
taken with the ps3 "eye" camera and explains why its pretty low quality.

[jonesy42]

@gipetto....Its the same qev as the one in wyz's video with the little slide valve
cheap ebay job ya know- its got chinglish written on it.

[Lockednloaded]

yeah, i meant to say 5/8 had a nOOb moment.

Ive, also got one of those rectangular black qev's that wyzz
done the video on, are they okay for 300psi?
probably fit in better and sit a little lower than the alpha qev

I've personally taken mine to 800 psi, but I try to keep it below 600 most of the time. It may fit better in your stock, but it also has much lower flow then your current valve.

[jonesy42]

yeah, i meant to say 5/8 had a nOOb moment.

Ive, also got one of those rectangular black qev's that wyzz
done the video on, are they okay for 300psi?
probably fit in better and sit a little lower than the alpha qev

I've personally taken mine to 800 psi, but I try to keep it below 600 most of the time. It may fit better in your stock, but it also has much lower flow then your current valve.

Thanks mate, im going too 300psi max, and 6mm calibre
is plenty for what i need...Is this qev okay for semi-auto though, or not?

[jonesy42]

Bottle threads on the regulator will be 5/8-18UNF. Outlet thread is 1/2-14NPS BTW.

Under the forestock is a better position IMO....if it's thin enough, a cutout in the butt stock perhaps? Largely dependent on how you prefer a rifle to balance. My preference is to have the balance forward on a bench rifle, and rearward if shoulder fired.

I will measure up to see if the scuba bottle will fit in the stock,..
As, it is sllightly heavier on the barrel end anyway, and that shoulld balance
it out a little... Then i could run the firing chamber under the fore
stock....ill check it out...

[Lockednloaded]

yeah, i meant to say 5/8 had a nOOb moment.

Ive, also got one of those rectangular black qev's that wyzz
done the video on, are they okay for 300psi?
probably fit in better and sit a little lower than the alpha qev

I've personally taken mine to 800 psi, but I try to keep it below 600 most of the time. It may fit better in your stock, but it also has much lower flow then your current valve.

Thanks mate, im going too 300psi max, and 6mm calibre
is plenty for what i need...Is this qev okay for semi-auto though, or not?

IMHO, the 1/2" QEV you have pictured is overkill for a 6mm barrel, but the "rectangular type" would be perfect for airsoft caliber. And yes, it will work semi automatically with a three-way valve