I was thinking a while ago, that it would be cool to make something like the gun below, from Star Wars Republic commandos

Where you see the wierd yellow things is where the resevoir would be. The gun would be CPS, but the gun would need to be a low pump style gun, as it is the Star wars version of a shot gun. The fast connect hose connections from Gardena or other companies could be modified so that when pulled past a certain point, it would release the resevoir. The pump would be complex, as you can see in the picture below, as it goes over the resevoir, making it difficult to create.

A ball valve with a modified release and a homemade trigger (and closing of the valve) could be made with a brass ball valve, metal, rubber bands, and PVC. You could change the spray so that it is wider spread, or highly accurate (this is still in "planning" so i dont have any pictures- this is all coming from the head).
Another idea by CROC

For those who didn't know, this topic is the WWc equivalent of <a href="http://forums.sscentral.org/t3961" target="_blank">http://forums.sscentral.org/t3961</a> at SSC.

If you're looking for more of a shotgun, I would definitely change some things regarding the design you posted at SSC. First of all, having a PC the size of the reservoir is extreme for any gun. And here, it would probably be better to have a really small PC.

Second, the bladder should probably be a fairly weak one. That way, you can use a large pump diameter so you need fewer pumps. The fact that this is only a shotgun means it doesn't need too much range.

Third, it would be best for the pump to be inverted. Ie, you're actually pumping water into the chamber while pushing the pump handle forward. It would be awkward to use a standard pump with the handle in that position.

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Now, I'm just throwing out an idea for a single-pump shotgun...kinda like the Splat Blaster or a manual-action Nerf gun.

It's probably best to use a spring, like in the Splat Blaster, for a single-shot gun. The pump distance, judging from the game, should only be 6-8 inches max. And let's say the maximum force applied to the pump should be 15 pounds. I'm thinking:

60 pound spring
2" length x 1" diameter chamber
8" length x 1/2" diameter pump

So what do you think?

For those of you who are wondering what the heck we are talking about, it would be best to read the original topic on <a href="http://forums.sscentral.org/t3961/" target="_blank">SSC</a>
I cut about a 6" piece of LRT yesterday, and loosely assembled about half of the gun. I need to purchase check valves, but I may be able to change my design a little bit to accommodate this. I originally had a foot-long section of LRT, but when I tested it for size... It was about 4 ft. long when filled with air. Sadly, the half of the gun that I got is all steel/brass, so it weighs a lot. The rest of the gun, hopefully will be plastic (exception of a washer in the pump). I might not make it a 1-pump gun, but I have several thoughts, considering that the LRT expanded right when I first pumped it. My pump is 3/4", but I might reduce it to 1/2" if I find it too hard to pump.
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So
8" length x 3/4" pump
6" length x 1/4" tubing (expands to about 2")

If you find the 3/4" pump too hard, I would just reduce the thickness of the bladder. Otherwise, you'd never get quick pumping.

The spring idea was just a thought I threw out there. LRT would obviously be much better, and you can still pump just once right before engaging for effect.

Steel and brass sounds incredibly heavy. If you managed to get the LRT from McMaster-Carr (did you?), then you might be able to get PVC as well.

Good luck with the design!

I did not get the LRT from McMaster Carr, I got it from Home Depot, along with most of the fittings requaired to attach it. Most of the PVC in Canada is not pressure rated, so I think I made a good choice. I need to get check valves before I can make any more progress, so I will probably go out this weekend to get some
~CROC