There are quite a few good .243 bullets out there. Here's a short list:

70 Gr. Nosler Ballistic tip.- varmints, antelope.
85 Gr. Sierra HPBT Gameking - good all around bullet
95 Gr. Nosler Ballistic tip - deer, antelope
100 gr. Sierra Pro Hunter - deer, antelope, black bear

I would expect any of these bullets to shoot golf ball size groups at 200 yards, although guns vary a lot in terms of what they like/don't like. IMR 4350 and H-414 are two powders that have worked well for me in a wide variety of .243 Winchesters. And use Remington 9 1/2 or CCI BR2 primers. Never use CCI 250's. Good luck. Roskoe.