20mm Airsoft Howitzer

Show us your pneumatic spud gun! Discuss pneumatic (compressed gas) powered potato guns and related accessories. Valve types, actuation, pipe, materials, fittings, compressors, safety, gas choices, and more.
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mako
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Thu Mar 05, 2015 5:28 pm

Hey, guys! I just *finished* my first airgun! :o Okay, yeah, it's not my 'first' actually, but it's the first one that's been finished to operational standards, instead of just going to 'proof of concept' and no further. :(

After building a small hammer valve for a project I'm working on (airsoft shotgun) I thought to myself, "Hey, I LIKE hammer valves!!" They're elegantly simple, remarkably efficient compared to ball valves, and much cheaper than QEVs. And they're easy to make. Since I had a couple of fire extinguishers lying around, I figured I'd make an airsoft heavy weapon for our frequent games. 8)

It started out as just the hammer valve and air tank, with no particular design intended. I was thinking about using it to make a shoulder mounted RPG type thing, but then I figured it might be more fun and more fair to build it into a heavy artillery weapon. And darned if it isn't just that!!! :shock: I test fired it at %40 of the planned air pressure with a shotgun style sabot with around 25-50 BBs in it. Ended up with a six foot BB blast that went about 60 feet. Not massive range, but that's not the intent. At the full power (planned 100 PSI), it should be firing around 100-150 feet with a much bigger spread. Perfect for war games. :D

What's that? You want pics? Okay, here's some to get ya started.
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Frontal view to show off the blast shield and barrel.
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Side view. You can see the bolt handle (bolt is inside the black 'firing' chamber) and the hammer (small green pipe and cap). The hammer springs are heavy enough to open the valve on their own, without the impetus of the hammer. The idea is to open the valve and keep it open, so all the air is used in a single shot. This was to increase power, but more importantly, to make it a single shot weapon. Gotta keep the game realistic. And fair. :wink:
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Pic with my little brother kneeling beside the gun, for size comparison. It's not huge, due to cost restraints. However, even if I had the money, I'd probably have kept it about this size, anyway. It already weighs abut 50-75 lbs, so anything bigger would be a PITA to move around and/or store after a game.
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velocity3x
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Fri Mar 06, 2015 11:10 am

Absolutely Magnificent! A truly beautiful creation!
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mako
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Fri Mar 06, 2015 11:23 am

Thanks very much! It's currently still needing some work (trigger mech and pressure gauge installation pending) but otherwise, it gets some serious wows. :D Even if the power doesn't turn out to work like I'm hoping, it'll still LOOK cool on the field.
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Gleedaniel13
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Wed Mar 11, 2015 9:47 am

Hands down for this one. This is very creative and very innovative. :)
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mako
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Wed Mar 11, 2015 11:48 am

Thanks. I gotta give the credit for the hammer valve to the other guys on here though. ;)

I WILL take credit for the mounting bracket, though. The strap that holds the air-tank on? Simple steel strap with a cam-locking latch from Home Depot. Works beautifully and doesn't stress the tank. Win-win.
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Ianbuckwell
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Sat Mar 21, 2015 8:26 pm

That looks brilliant, you just need something like this to tow it

http://www.toydome.co.uk/petrol-2-seate ... -166-p.asp

That would put a smile on any kids face!
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Wed Apr 15, 2015 10:13 pm

I might be wrong due to being a little new, but could you nol load a light foam ball as the last thing in the barrel? Then it shoots bbs and a large caliber rounds. I don't know what the velocity of the ball is, and safety is a concern, but I could conceive of a anti vehicle weapon.


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mako
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Thu Apr 16, 2015 10:36 am

@Ianbuckwell: hahaha. That's awesome. Smile on a kid's face? Well, I must still rate as a kid, then. XD

@Hunter62610: I could and actually thought about it. However, the barrel size is a little odd, meaning most commonly available spheres are either slightly too large or small enough that they let too much air escape. I'm currently working on replacing the barrel with a longer, larger caliber, though. I might be able to find ammo for the new one.
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Thu Apr 16, 2015 2:36 pm

mako wrote:@Ianbuckwell: hahaha. That's awesome. Smile on a kid's face? Well, I must still rate as a kid, then. XD

@Hunter62610: I could and actually thought about it. However, the barrel size is a little odd, meaning most commonly available spheres are either slightly too large or small enough that they let too much air escape. I'm currently working on replacing the barrel with a longer, larger caliber, though. I might be able to find ammo for the new one.
You could cut a custom foam spud out of foam sheets.
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The bigger barrel sounds cool.

I would also love to see this adapted to a be a mobile BBMG turret. Since wheight is not a issue, you could hook up a ridiculous triple barrel BBMG.

What do you mean 300 BBs a second is to much power?


When life gives you lemons, concentrate their Citric Acid, and load into a home brew CO2 driven Super duper soaker.

Then show life who's boss.
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dart guy
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Tue Apr 21, 2015 11:28 pm

I vote exploding shells, like rounds that when they contact something they create a spray of bbs. Pneumatically
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