SpudFiles

Here is a mini m203 I made recently.

1 1/4" parts.
1/2" barrel.
Fill valve is an 1/8" Schrader.
Exhaust valve is a 1/4" pop-off.
Rubber sheet for diaphragm.

No test fires yet, waiting to glue to cure.

I couldn't resist... I just looked so shiny sitting there on my table.

All I can say is wow... this thing scared the fuck out of me. It is fucking LOUD!! This little packs a heck of a punch. It shot a nerf dart so fast I couldn't see it!

Very nice work, you should add a handle to it though. Aslo add some kind of trigger to the valve. Shoot that soda can which is in the picture.

How long is your barrel?

nice. cool, and a lot of power for the size, because It's a diaphragm valve cannon. (obviously)

Oh, the barrel is probably about 5 inches.

attach a string or a cable to the pop off valve, then drill a hole straight through the top of a water bottle. then cut a hole in the bottom for the barrel, and cut the barrel off flush. then it would be disguised as a water bottle. to fill it, you could unscrew the top of the water bottle, and hook up a little bike pump, one of the ones that you mount on a bike frame (concealable) and hook it up, then pump it up. that would be slick. a concealed diaphragm cannon. tip the bottle up to take a drink, then pull the string.use It to fire peanuts at sporting events.

hehehe good idea.

I shot a glass marble at my shed. It didn't hurt it but it bounced back real far. I also shot water. It was awesome but screwed up the gun. I had to dry it before it worked again.

I'm actually really impressed with this thing1

that's cool. what did you make the diaphragm out of? Is that krylon fusion?

Yeah, it's fusion. I made the diaphragm out of those cheap bathtup stoppers from home depot. I already burst one at 90 psi.

Cool idea for the concealed gun in the waterbottle... i am definitely going to have to try that now!

I wouldn't cut anymore of the barrel off... 5" is VERY short, and cutting anymore off would lead to significant power loss. Good idea using a diaphragm; I heard they work better than pistons for short barrelled guns

Love it, could you post some damage pics?

you would pull the string hooked up to the pop off valve trough the hole drilled on the top ( just to clarify because I hadn't explained It in my previous post )

Its official: I started building one of these today! PVC arsenal, its just such a cool idea! I dont have any threaded plugs near me (only cleanout caps), so I build one myself with PVC rod and a male adapter.

Mine is going to be 1.5" pipe, with either a 3/4" SCH 80 CPVC barrel or a 1/2" SCH 40 barrel (leaning towards the 1/2", only because I don't paintball)

i dont know this for sure but isn't cpvc weak and shouldn't be put under pressure.

I beleive the rating of 3/4 cpvc is around 280 psi but not sure.

Good luck with it though!

Quick tip: grind down some 1" pipe to slip into the plug. This thickens it up a bit so the diaphragm won't get sucked in as easily.