3 shots per round starts at 50 yards and moves out my 50 yards each round. They go out to 500 yards. No elimination and high score at the end wins.
Five hundred yards!, that is a long, long way for a pistol cartridge. I thought 200 yards was a long way for a 44 Magnum, but 500 yards, that is crazy. Whatever rifle is used, it will require an ungodly amount of elevation adjustment. Maybe someone with a calculator can give an idea of the MOA from 100 yards to 500 yards with a 44 Magnum.
At that distance I have no idea what would be the best ballistic round. Something else, wind reading ability will trump claimed 50 yard accuracy. There will be lots of claims that one cartridge shoots 1/2" better at 50 yards, 100 yards, but at distance, they will be all blown tens of feet with a small wind change. That was one heck of a windy day!
A big wind change, I cannot image getting on target at all. I have a story about wind. One National Match at Camp Perry I was in the pitts complaining about the wind at 600 yards the previous day. A near by shooter came stumping down to my point to tell me, the year he won the 1000 yard match with USMC M14, he had full right windage and was aiming three targets to the right of his target!. Now a M14 has about 33 MOA of windage, so half of that would be 16 MOA. At 1000 yards that much windage is 16 feet, and then lets assume targets are 15 feet center to center, so his bullet was drifting some 60 feet from the point of aim, to point of impact!