Yeah I know about needing the 4" pipe between the fittings. I'm just lazy and didn't feel like modeling them. The reason I've got everything butted is because it keeps everything compact. I'm all about cosmetics. If I did my math right with everything butted I should be able to use my 4" barrel. I a...

I fixed it. I forgot to do something the first time. My model is missing my bumper. I used one of thoes temporary rubber caps but I cut a big hole in it so air can get from the inlet (in the cleanout) to the pilot area. A 3" temp cap fits perfectly inside of a 4" cleanout cap.

I know that this isn't a pic of the real thing but it is an accurate 3d model of it. I would put up some real pics but right now it is made from DWV fittings. I'm going to rebuild it with NSF-pw fittings but I'll have to order them off the internet. Most places don't carry 3" and 4" water supply fit...

thanks for the input guys. I was going to try to make it as light as possiable and seal it with o-rings. I'll will try and get some pics up as soon as I get the plastic. I think I am going to get this "Ultra High Molecular Weight (UHMW) Polyethylene" from http://www.usplastic.com

I'm gearing up to build my first pneumatic potato gun and I have some piston questions. I will be building an over-under with the piston in the tee. I understand how they work and plan to machine my piston from a 3" x 6" piece of some kind of plastic (to be determined). I've got the design in my hea...