I can only speak to the .45 caliber 350 grainers. They do load reasonably easy if you apply a small amount of lube to the grooves (they are designed for same). They're also a very accurate bullet. I don't shoot them in my White .451 but have shot them from my Encore .45 with very nice results.Can only guess that the .50 calibers would load and performessentially the same. I believe the OEM for those bullets was Buffalo Bullets and they may still have some very similar product in their line.

Don't hold your breath on those SCS/SCB critters. A few were made but no real production. The only one I knew that shot any of them didn't think much of them.