While what I have posted is far from complete, I have started posting a derivation of a relatively simple model of a pneumatic gun on NerfEngrWiki. Feel free to use the comments section to ask questions, etc., if you have any. I don’t suspect many people will have questions, but I do know a few folks are carefully examining what I have developed.
I also have started working on a page about valves with a focus on modeling the flow through valves for pneumatic gun models. So far I have used this page to derive in detail (something I have not seen before) one of the valve flow equations that I have seen.
More pages will be developed. I’d appreciate any contributions that can be made, too.