The power belts belong to the 50's and 60's eara, one to 1.5 grains per caliber they can be made to work but the majority has bad experience with them.
If you have the option of sabot-ed bullets try the Shock Wave [one of the most accurate for long range] or the Gold Dot 250gr which I believe to be the most effective reasonable priced bullet. If you are hunting massive game then the more expensive bullets are appropriate Nosler Partition, Lehigh and barnes. About the same price as those power belts which are on the bottom of the majorities list of bullets if they make it at all, I am about to melt some to make round balls.