Andy, I enjoyed part one of your "Air to Air Gunnery" feature. Detailed stuff! I like that. Having some background knowledge about the systems that flight sims simulate adds to the sim experience. I'm not thinking just about the cannon itself (rounds and rate of fire), but also the "virtual world system", ie. the ballistic properties of the projectile path, the effects of gravity and pulling Gs away from the bullet stream.
Regarding projectile density and rate of fire, current sims must simplify (for obvious reasons --- adding 2000-6000 fully calculated and collision tested objects every second is too much for any hardware I guess :-). Add that sims use a discrete iterative simulation model (I guess), and the distance a projectile travels during the iteration interval. Unless a sim uses advanced interpolation techniques it can't be very accurate.
Do you have any comments on how sims do/simplify this?
I guess one simplification is to have fewer elongated projectiles (line segments), as well as using simplified damage models, ie. increase destructive power.
PS. Liked your "CAS in Vietnam" article also. Very informative.