Plans for a marble sniper i am hoping to build soon.

[Extrusion]

Well, i have been gone for a while and im hoping to be able to save up to build this marble sniper cannon soon, i made some plans for it in paint maybe you can check the out and give me some suggestions/comments before i start the build.

This will be an all metal gun, the chamber will be either 1" steel or black iron, and the barrel will be .5" copper.

(The 200 PSI Safety Pop-off valve is mostly so i don't blow the QEV wich the one i have is only rated up to 250 PSI.)

Im hoping to get this done soon, but the metal pipe around here is insanely expensive.

I got the basic design from Hotwired's Copperhead Prime wich is a good design, i just hope the .5" copper barrel will fit marbles as good as .5" black iron does.

[jackssmirkingrevenge]

i just hope the .5" copper barrel will fit marbles as good as .5" black iron does.

Technically, if they have the same dimensions, it's irrelevant what the pipe is made out of...

Also, why do you need the 200 psi pop-off valve? Doesn't your pump have a gauge? Personally I think it's an unneccessary complication, after all just because your QEV is nominally rated for 250 psi, it doesn't mean it's going to explode when you hit 251 psi.

[ShowNoMercy]

The ID for cast iron (which is what I think you wanna use?) is 0.622" for .5" nominal sizes. The ID for copper are, 0.527, 0.545 and 0.569 those are for the different types of copper. Im not sure what type of metal you are using but they dont match if you use cast iron.

[A-98]

one problem with the design, you need the schrader to be on the pilot side, it wont fill from the chamber.

[Extrusion]

one problem with the design, you need the schrader to be on the pilot side, it wont fill from the chamber.

Ah, thank you, i really don't know how QEV's work, most of the pneumatic cannons i have built used a spring operated ball valve.

Would have sucked is no one told me about that and i had to find out the hard way.

I'm going to be getting a different QEV wich will be easier to use with the new design i drew, it's only a few dollars more.

Here is the new concept i am thinking of.


I have also found a scope + scope rings that im almost sure i can somehow fit onto this, as for sighting it in i found a barrel laser (One of the things you fit into the barrel and turn it on and it shoots a laser beam out of the barrel) all i would have to do is put it in there and adjust the cross hairs onto the laser dot.

@Jacks
My air compressor fills my other pneumatic (with a 2', 2" chamber) up pretty fast, i know the QEV isnt going to explode the second i hit 251 PSI, but i just want it on there to feel safe, i don't see the problem with it really.

@ShowNoMercy
I'm talking about .5" black iron pipe, wich i use for a barrel on my other pneumatic cannon, it fits marbles well, but i don't think it is "cast iron".

[A-98]

check this topic out. i have a few designs, and i have explained how qev's work pretty well (in the diagrams atleast).

the problem with your above gun is that the qev cannot be oriented like that. ill draw how it would be oriented in the type of cannon you want.

sorry for the lack of fittings, but you get the idea.

[noname]

You're not going to be able to aim very well unless you mount it, you need to work a shoulder stock into your design.

[Extrusion]

check this topic out. i have a few designs, and i have explained how qev's work pretty well (in the diagrams atleast).

the problem with your above gun is that the qev cannot be oriented like that. ill draw how it would be oriented in the type of cannon you want.

sorry for the lack of fittings, but you get the idea.

Ah, again, thank you!

I tweaked the design a little, but found out that it wouldn't be very comfortable to use the scope with the tire valve sticking in my neck when i aim with it so i added a laser pointer mounted into the wooden barrel support.

-EDIT-
@noname
I thought about that, and tweaked the design yet again, i decided to add a tee to the blowgun and run some pressure-rated hose from where it was to where it is now, basicly i just put a tee onto the blow gun, then screwed a barbed hose adapter onto the other end of the tee, i did the same for the tee attached to the QEV, i would then use the tee coming from the QEV as a shoulder mount.

This is just a quick fix for my aiming problem, i'm a bit tired at the moment (11:00PM here)

[A-98]

hell, if your going to do that you might as well extend the pilot "T" and make it long enough for a stock.

i take it that you want to be original, and therefore you are not using the same layout as Hotwired's copperhead prime?

[Extrusion]

hell, if your going to do that you might as well extend the pilot "T" and make it long enough for a stock.

i take it that you want to be original, and therefore you are not using the same layout as Hotwired's copperhead prime?

Well, i could extend it, mcmaster doesn't sell exactly 4' of .5" copper pipe, the closest to 4' is 60", or 5' so i could use the extra foot to extend the tee for a shoulder mount, i'm new to copper, and having to solder it so i don't know about all the fittings i will need (No idea how i'm going to connect the pilot tee, barrel, and chamber too the QEV, the QEV is threaded and the copper pipe is not, and i don't know what fitting to get.) if there is someone kind enough to look at my plans and go on mcmaster and order all the fittings i will need just so i can get a range of the price, i'm probably just going to make the chamber copper since it is cheap.

I would basicly just need someone to find the fittings i will need for attaching the barrel, pilot tee/shoulder mount and chamber to the QEV. (No need too add tire valve, blowgun, pop-saftey valve, etc. to the order, just the pipe, QEV, and needed fittings.)

Here are the parts that i'm going to need.

5' of 1/2" copper pipe (Barrel and shoulder mount/pilot tee)

2' of 1" copper pipe (Chamber)

1" end cap

3/4" tee

3/4" 90 degree elbow

1" to 3/4" reducer

That's all i know, i don't know about the fittings for connecting the chamber to the QEV and such, so if someone can go on mcmaster and find them for me, i would greatly appreciate it.