The Hammer Shotgun

Cannons powered by pneumatic pressure (compressed gas) using a valve or other release.
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I believe this to be a first for Spudfiles, a nearly all clear Hammer Piston Pneumatic.
This was a relatively easy build, taking about 4-5 hours to complete. The chamber is made from Polycarbonate, as such the pressure used is only limited to how lucky you are feeling, i would feel safe with a working pressure of around 200psi. There are no parts that can shatter if it were to fail.
The end caps are made from Acetal as is the piston, the sealing face is Polyurethane as is the bumper. The barrel is Acrylic.

There were two reasons for building this, 1. Coolness points 2. To show noobs exactly how these types of guns work. More for the coolness factor though :P

The barrel is 16mm, as such it is perfect for marbles, i'll be making my own ammo so i'll use marbles as the tip. The chamber is just under 2". Velocity-fast.
Image
Whole cannon
Image
Piston extended
Image
Piston in fire mode

A shout out to JSR for giving me the idea of the Hammer Piston :D
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MrCrowley
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:shock:

Coolness factor = ∞

No really, that looks great. How's performance?
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Killjoy
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Damn that looks cool. Funny, I just finished a hammer piston valve prototype a couple weeks ago, but you beat me to the posting.

Excellent job once again.
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Lentamentalisk
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sweet!
My only comment is that you need to stop making such really cool cannons, its embarrassing the rest of us.
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MrCrowley wrote:How's performance?
To say that i was surprised at the performance is an understatement.
I tested it today at around 100psi and even with light weight plastic rod as ammo it is out of sight before you get to see it.
With another round i used (brass hollow ass) the spray can i was shooting at said "Holy crap, this is gonna hurt" then got blasted in a puff of blue paint :P
I will guess that the velocity is around 600fps but it's only a guess.
I will post some damage pics for you guy tomorrow if all goes to plan.
Cheers for the great head swelling comments too, always makes a bloke feel good!
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jackssmirkingrevenge
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Once again you leave me gobsmacked, that is just beautful!

must-get-hands-on-lathe!

My one very small gripe is that due to the low-ish pressure, I would have made the chamber bigger. Also, is the portion of the piston that seals against the barrel airtight? Because if so, I think it could be impeding the hammer ìdea's function and working more like a conventional piston, perhaps you should drill a few holes in it?

One last point, you can't show us something like this without a video :D
hectmarr wrote:You have to make many weapons, because this field is long and short life
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jackssmirkingrevenge wrote: My one very small gripe is that due to the low-ish pressure, I would have made the chamber bigger. Also, is the portion of the piston that seals against the barrel airtight? Because if so, I think it could be impeding the hammer ìdea's function and working more like a conventional piston, perhaps you should drill a few holes in it?
:D
Point/s taken, maybe i will look at modifying the piston, i get what you are saying about it acting as a normal piston, yes it is airtight but i can as you suggested "put a few holes in it", bloody drilling holes in it, i'll have to make the holes look pretty! :D :P

Vids will happen too.
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jackssmirkingrevenge
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It doesn't have to be holes, you could just cut trim the circumference like so:
Attachments
piston.gif
piston.gif (1.98 KiB) Viewed 5567 times
hectmarr wrote:You have to make many weapons, because this field is long and short life
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What i'll do is cut six grooves around the perimeter, after i make a new front half. I want to remove the o'ring to reduce friction and the current one will not suffice as it is too loose a fit without the o'ring. Thanks JSR.
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jackssmirkingrevenge
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That would work too, remember the front portion only has to be big enough to seal over the barrel, and contact the chamber wall enough to be stable, so the more material you remove the lighter it will be and the quicker it will open :)

For those who might be wondering what this whole "hammer piston" malarkey is, this is how it works:

Image

Also, do you have a bumper to cushion the impact of the piston against the chamber endcap? Granted the piston does provide a "braking effect" but I'd still put some rubber there to soften the blow.
hectmarr wrote:You have to make many weapons, because this field is long and short life
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clide
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Darn I need to stop slacking, you beat me to posting my clear piston valve that I built months ago. :(
But I don't have the cool factor a clear barrel to go along with it. Oh well I still got some tricks up my sleeve. :wink:

Nice work on the gun, looks really great.
<a href="http://gbcannon.com" target="_blank"><img src="http://gbcannon.com/pics/misc/pixel.png" border="0"></a>latest update - debut of the cardapult
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clide wrote:Darn I need to stop slacking, you beat me to posting my clear piston valve that I built months ago. :(
But I don't have the cool factor a clear barrel to go along with it. Oh well I still got some tricks up my sleeve. :wink:

Nice work on the gun, looks really great.
I beat the infamous Clide!!

Any chance of seeing your creation? :P
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MrCrowley
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Infamous? What's he done now... :D
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jackssmirkingrevenge
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MrCrowley wrote:Infamous? What's he done now... :D
Shown a penchant for ventilating ceilings? :D
hectmarr wrote:You have to make many weapons, because this field is long and short life
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SpudFarm
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that just as to be cool if you put in some LED lights. think this
"at night load you cannon and light the LED's then shoot and there becomes fog in there so you can see the light in a good way"

anyway AWSOME creations you got:)
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