Any of the inexpensive factory 100-grain loads, whether Federal, Hornady, Remington, Winchester or whatever.
An update on this 243........
I mounted a 3x9 Leupold and as suggested by several tried four factory 95 - 100 grain loads, 2 Federal, one Winchester and one Hornady. The 100 grain Hornady Whitetail was the best by far in this rifle with several 3 shot groups at 1/2 inch, some slightly less. And this from a $279 Savage Axis rifle! Performed well in the field also. One shot at just under 250 yards.