Good analysis. Can't say that I've actually used much calculus in a couple decades but the math makes sense. The tables should be very easy to reproduce from readably available data.

I heard that 7.62 x 39 brass was rumored to be found on concert grounds but I've seen nothing to confirm it. Lies, lies and more lies??

AK FMJ ammo has muzzle velocity at 2430 f/p, so distance should be much less than the 250-275 feet determined from his analysis.