For a 200yrd shot, try the tried and true Remington 100grn Cor-Lokt. Not a big fan of it, but I have used it with great result on deer in PA woods. I load 95grn SST's now. Waiting for my nephew to poke one to see how they work. Your rifle may like the Remmy load, it may not. If it holds an 1.5" or 2" at 100yrds you'll be golden. If you want to start reloading the 243, then I would suggest the 100grn SPBT, Hornady 95 SST, Hornady 87 V-max, and Sierra 85 HPBT. All proven to anchor deer with accuracy and authority.
For hunting deer in a long range application, it was suggested to me by our .308 enthusiast and guru (Michele Eichele) to use the 200grn SGK because it has a lower opening velocity of 1500fps. He also said to try the 208 Hornady A-max. I plan to use 155's (SMK Palma, possibly Berger 155.5, or the Nosler Custom Comp. Even considered the Lapua Scenar) for varmint and target applications. This should help to buck wind nicely and perform admirably at ranges past 1000 for gopher's. According to ballistics. I don't go sub sonic with 155's until after I run out of turret adjustment anyway. So it really isn't that imperative.
Tank