I agree with Tim on the 100 gr. Federals. My 11 year old son can destroy the bullseye at 100 yards with those.
I also handload, and found a load that seems like it will work out (although I am still experimenting). I am using Hornady 100 gr soft points, over 39.5 grains of H4350. This is from the Hodgdon manual, and is 1/2 grain under the recommended max load. I was able to shoot a three shot group that was 3/4" at 100 yards, with two of the shots touching.
Based on interpolating the pressures in the Hodgdon manual, this would be about 50,000 CUP.
Good luck with the .243.
Tim