Wow, some good conversation going on. Thanks for all the input. I really had no idea that there was this much interest or research done upon CB ratios and the more technical aspects of spud gun design.

BTW, in a combustion gun there is a very distinct thing that occurs at the optimal CB ratio. If you plot projectile velocity versus projectile position there is a maximum velocity at a unique projectile position. If the projectile is still in the barrel beyond that point then it is actually ...

**Edited post
I generated a curve for velocity by doing a little math, The general shape and slope of the velocity curve reflect the acceleration results. I agree, Some interpretation has to be done with the acceleration graphs to learn anything useful. However, the same conclusions can be drawn ...

You might want to non-dimensionalize what you wrote. I non-dimensionalized the adiabatic pneumatic gun project and found some interesting things . Namely, I found a simple way to do some design tasks that would be nearly impossible otherwise (i.e. pick performance first and scale up the optimal ...

Here is my EDITED code with all work done in metric. I used a force analysis to determine the projectile acceleration. If you want, I can justify it because the derivation isn't all that obvious. I used the ideal gas law to incorporate the change in pressure as the projectile moves along the barrel ...

I found a unit error in my calculation and as a result, reworked everything in metric. I converted back to english before graphing and then edited this post.

I'm new to this site so I don't know if this has ever been posted before but I figured it would be helpful to some people. There seems to be ...