What would be the best way to seal up the gun super tight, the idea is to charge it with a pump, carry it around charged, and use it one time in a 2 hour portion of a game. So ideally it would not lose a significant amount of air in that time

I think you found my thread..

Be sure to seal all cut edges of the pipe exposed to chamber pressure. I found some of the core by some manufactures will bleed air through the core. I had to seal the edges of my 2 inch pipe ports to prevent air from getting in the core under pressure.

It was your ...

Angle doesn't matter a ton, it rather lob it than blow on the gun. I was thinking about 30 degrees max though, for realism/accuracy sake.

the only weight I can find is 8oz which is .226 Kg for the kinematics

I have been planning to make a cannon to launch Nerf Mini Vortex footballs. The idea is to make a man portable "rocket launcher" for airsoft that is 4" diameter by 40" long using a 2" barrel inside of the 4" chamber and a pilot valve (I have been researching this quite a bit). As you all probably ...