After 45 years of inactivity, I'm looking to drag my heavy varmint benchrest rifle out of storage and get back into benchrest competition. The cartridge is the wildcat 23-40 based on the 223 Remington cartridge. It is very similar to the 223 Ackley Improved, but slightly shorter total cartridge length and slightly longer neck. Back when I was actively shooting, I used W-748 powder driving 52 grain match bullets. This was partly due to the fact that I loaded between matches at the range, and the powder measure would throw a consistent charge of W-748 being that it was a ball powder. However, I know there have been major improvements in powders, with many now being temperature stable and yielding small velocity deviations from shot to shot. W-748 is not a temp stable powder, so I'm wondering what my best powder options would now be for this cartridge. From online research, a lot of folks have mentioned Hodgdon Benchmark, Hodgdon Varget, Hodgdon H335, Hodgdon H4895, and Alliant Reloder 15. Right now, almost all powders seem impossible to find, but I'd like opinions of what powders might yield the best precision for this benchrest cartridge.