I was reading the thread on Flat Shooting and struggling to think about the suggested calibres and reported performances etc. and what they meant. It occurred to me that it might be possible (and helpful) to combine some key figures in a graphic that could then be used to compare two situations (either calibres, bullet weights, powders etc.).
It could work by fixing some parameters - such as target size, altitude, temperature etc. - for both situations and then choosing variables - such as bullet weights, velocities etc. Both could then be shown on a 4x4 grid like this:
It's probably only useful (if it is useful at all) when point blank range is crucial in a cartridge/calibre choice.
Any way, I just thought I'd see what everyone else thought - is it worth thinking about a bit more? (or does something doing the same job already exist!).