50 cal. Pneumatic Sniper

[maverik94]

I acually Built this baby a month or so ago. It's a seriously powerful pneumatic.



Specs:
Chamber: 1 1/4" & 1" PVC
Barrel: 1/2" PVC
Fill Valve: Schrader Valve
Release Valve: Modified 1" Orbit Watermaster Sprinkler valve
Exaust Valve: Blowgun Valve

As far as performance, this thing really packs a punch, I dont have a compressor, so I use a foot pump to fill my guns up, so I dont use really high pressueres, but at 60 psi I was able to shoot 1.5" long wooden dowels wrapped in duct tape 300 ft! I used a primitive chronometer to figure out it shoots about 270 fps at 50 psi. I was able to shoot through a 3/8" piece of particle board from 50'. This gun has some pretty big recoil too, compared to my old ball-valve gun, this thing really kicks back when fired. It was originally going to be breech loading, but I decided to leave it muzzle-loading. I am planning to, instead of painting it, wrap it in camo duct tape, like my ball valve rifle.

This is the modified sprinkler valve



This is me holding my new baby



This is the view looking down the barrel when you are about to blow away anything in its path



Here is a damage shot. I used a sharpened wooden dowel from about 20 feet with 55 psi. It shot clean through a campbell's soup container, the slug kept on going, but I lost it, so I'm not sure how far it went.

[SpudsMcGee]

Damage Pics Please...

[jackssmirkingrevenge]

I would have gone for a smaller chamber, that would make it easier to take to higher pressures (a good track pump is not expensive and will do 150 psi easily)

[maverik94]

yeah, I guess a smaller chanber wouldhave worked, but I liked having the chamber underneath the barrel so I had a better hand-hold. Also, it gave me a place to tie the barrel down, because, as I am sure you know, pvc is always a little bit bent, so I straightened it out by tying the barrel down to the chamber. Also, wouldnt a larger chamber pressurized at a high pressure have more force than a small one? Anyway, I added a damage pic on the topic.

[jackssmirkingrevenge]

Also, wouldnt a larger chamber pressurized at a high pressure have more force than a small one?

This is true, however a smaller chamber is easier to take to higher pressure and for a given quantity of air, lower volume and higher pressure means more power.

Scroll through this post for some statistics proving the point

[maverik94]

Thats true I guess, but since Im not going to go above 60 psi on this gun, I think a bigger cahmber is better. If I pumped this chamber up to 50 psi, and a 6" long cahmber at 50 psi, the bigger one would have more power right?

[jackssmirkingrevenge]

Bigger chamber will always equal more power, but it comes to a point where the increase in power is hard to notice. Why are you sticking to such low pressure?

[maverik94]

because I dont have a compressor, I only have a foot pump. Also, Even though Im using pressure rated pvc, Im afraid to use much higher pressures than 60 psi. Also, my blowgun valve is rated only to 90 psi, and my sprinkle valve says safe operating pressure is 80 psi or less.

[LCTChamp]

Blowguns and sprinkler valves have both been used up to 120 psi many times without failure. If the parts would fail it would just be the diaphragm or inner parts which wouldn't cause shrapnel. Looks pretty clean and easy to hold. Great job!

[jackssmirkingrevenge]

Blowguns and sprinkler valves have both been used up to 120 psi many times without failure.

Agreed, sprinkler valves are usually good for at least 150 psi, I would be confident in taking this design to 100 psi or more assuming the pipe is pressure rated.

[maverik94]

ok, yeah, the pipe os pressure rated of course, It's cheap here in the US anyway. Ok, I might try it at higher pressures, The blowgun valve is not what I'm really woried about, whats the worst that can happen? the spirng flys out the bottom...big deal. It cosy about 6 bucks anyway. However, the sprinkler valve I bought from, get this: Amazon.com! Yeah, a book retailer that sells sprinkler valves, however, it cost me 19 bucks, so thats a pretty big hunk of cash (for me anyway), so I dont want that to break anytime soon, But I'll try it at higher pressures I guess. Thanks lctchamp for the positive comment too.

[Tcoz370]

theres a differance between opperating pressure rating and what it can hanldle for only a fraction of a second. the valves dont expirence pressure for very long at all.

[jhalek90]

That looks really good. im a fan of 1/2'' pvc barrels on air guns, as they can shoot nerf darts fast enough to make your head spin.