After I use up my Barnes bullets I may start using these. Basically the same as the Hornady SST bullet, just that it doesn't say "Muzzleloader" on the package. $27 for 50 is a lot cheaper than muzzleloader SST's as well.
Hornady LEVERevolution Bullets 450 Bushmaster (452 Diameter) 250 Grain Flex Tip eXpanding Box of 50 - MidwayUSA