I put together range cards for the 88 AP/AA, M4 HE, and M4 rockets about two years ago. They are clear plastic overlays that I scotch tape to my monitor. The way I gathered the info was I went into the practice arena, set up the target icon at a set distance (and target elevation in degrees above horizon, for AA), and hammered away at it methodically until I got a hit, and marked that gun elevation on the overlay. It got interesting with the 88 bursts out at 10k. The overlay cards work like a charm, but the whole effort kind of got boring. I rarely use the M4 rockets or HE unless I'm close. But every now and then I'll tape the 88 overlay up, nail bombers at 8 or 9 k, and get called a cheater or a lucky bastage. One of my records is nailing 2 B-24's with one burst at 9k away. I finally have film editing capability, so maybe over Christmas I'll put a film together on it.