The Backstory/How I wound up here:
Earlier in the year I was informed that our squadron would be holding a Dining-In. This is basically where a bunch of air force guys put on camo uniforms and go eat MREs in some shady venue. However, this year one of the officers who is overseeing the event wanted everyone to bring a water gun, and for there to be squirt gun battles over dinner (don't ask me why...) So being the inventor that I am, I decided that I would go for something a little geekier and crazier than the average guy. I came up with the idea for a huge, intimidating, automatically pressurizing super soaker powered by 300psi CO2 gas (yeah, I'm a mad scientist =P) Anyway, when I was younger I had a stock of super soakers so I figured that one of those would work nicely, but not wanting to ruin a cherished childhood heirloom I decided to go to target and pick up one there for cheap. Unfortunately, I learned that the 'good old days' of the super soaker brand were long past and they no longer made the CPS series and they're now selling on Ebay for like $200 (I was like wtf...)
SO I grabbed my old CPS2500 and I got to work:

The Mod:
So the first thing I did after I grabbed my old CPS2500 was I decided to paint it to look more appropriate to be carried around at a military event.

Yes, that's the hood of my car under the CPS =)
Then I gathered the necessary materials for the mod. I have images of them but I have found image sharing sites tend to delete images after time so I have listed the components as well. I also bought some 12g CO2 canisters but you can get those at any sporting goods store. You can also use the large paintball CO2 canisters as well.
McMaster:
- Miniature 1/8"NPT brass miniature air regulator 5-50psi range
- Brass 90deg elbow 1/8"NPT-1/8"NPT male pipe fitting

Ebay:
- Paintball quick change 12g CO2 adapter
- Paintball CO2 fill adapter remote on/off 2 port gauge
- 6" SS braided hose

To be continued... I'll post more pics of the mechanism/firing when I get it all assembled. Basically all that's left to do is assemble the thing, adjust the regulators and drill a hole into the CPS2500 reservoir for the braided hose, seal it up and the thing should pressurize itself =)