I am starting to think that Pneumatic is the way to go because of the ability to control the pressure. What is the optimal chamber to barrel ratio or is there one? Like if I have a much larger chamber than the barrel? The barrel will be about 3 inch (76.2mm).

I forgot to mention that this will be a breach loading design similar to http://www.youtube.com/watch?v=rqp5GMs2IYc but scaled up in terms of power source. In the way of range I was hoping to achieve .5 to 1 mile and yes I am willing to build withing tight tolerances (would not bother adding an elec...

I am designing an artillery type cannon that will be aimed by a sophisticated electronics system. The cannon itself will be made of metal. The projectile will be between 3-5 lbs and will be stabilized. A) I would like to know which platform (Pneumatic, Combustion, or Hybrid) offers the greatest repe...

Damn all i can render is a stick man on ms paint

Don't think that you'll get the range that you want. I suggest something like kipkay shows on metacafe using a laser, mirrors, and a light sensor. Would not be that hard to set up a mine and 1 mirror reflecting on the sensor.

Where are the cheapest regulators for co2 for 120 psi?

They look expensive. Where are the cheapest ones?

A broken piece of brass.

Where can I buy a regulator locally. Are there any stores like home depot that carry them and if so which are the best for a paintball tank?

I thought about something like that but I need portable. I will be running through dark rooms getting shot at from odd angles and such while carrying and using an airsoft aeg. A backpack would weigh me down. I think that a co2 tank with a pressure regulator is starting to sound like what I need and ...

I looked up the piston valve and it seems: A. Too Complex B. Too Expensive (my whole cannon cost 10 bucks to make) C. Too Bulky (Unless there are really small ones out there)

Well.. How brittle? I don't want this thing blowing up on me or anything. And where do i get a regulator?

Ok I found out about regulators, but where do I buy one?

I'm sorry that I am unfamiliar with some things due to the fact that I am a cannon noob, but what is a regulator?

Where do i get the proper tread to thread onto the 1 liter bottles though?