trophy hunter, If you want the best combination you can get and you can use sabots where you hunt the way I would go about finding that fit is:
To aquire a set of different thickness sabots
a set of the weight bullets you are interested in , in .451 ,.4515,.452
Take out the breach plug and try all possable combinations, the one that loads just a bit tighter than you would prefer will likly shoot the best.
If you choose to or need to go with the other style try a 300gr Sabortooth from harvestor, if you feel you must use PB's use the heavy ones with no more than 90 gr of RS or the equvilant thereof, most problems with power belts are from loading with more powder than is recommended by the people who make them. Lee