Determine the rate of twist of the .243 you are going to shoot. The early .243s had 12-14 twist barrels. The would not shoot the heavy bullets and this gave the .243 a bad rap. When I build .243s now I use 1:8, twist barrels. The 85-100 grain bullets work superbly in the .243. 85 grain Barnes XXX, 90 grain Scirocco, 90 grain Accubond, and the 85-105 grain Partitions. All work great in a fast twist .243.
I like H-4831SSC, H-4350, N-160, and Winchester 760 powders.
Nat Lambeth
NAT-I have been shootiing various .243"s since 1968. which of the rifle makes/ models had the 12-14 twist barrels? mine have all been deadly accurate and light recoil and i have used them on everything from elk, deer , antelope coyotes, fox, bobcat .......... starlings, crows.