I use Hornady's 250gr (.452) 45 cal. HP/XTP bullet with Harvester Crush Rib (black) 50cal. sabot and only 70gr by volume of BH209 in my T/C Impact. Never ran it over a chronograph it even though I have one. Even at a low velocity I've found the bullet to do a bit more damage to deer than I like and will eventually switch to the 300gr bullet of the same brand and design.
It would surprise me if you didn't find the Harvester Crush Rib sabot below to not load easier than that Hornady.
https://www.grafs.com/retail/catalog/product/productId/5464
