You are correct. Sabots were first used in cannon, and much later I think adapted to small arms. The sabot allows you to shoot a lighter faster bullet from your 50 cal. if that suits your style of hunting. There are several types and thickness's, allowing use of 44 cal, or other diameters bullets. I have some sabots which allow me to use .41 cal. bullets.
Work up loads with each, but you will find generally the sabots load easier and recoil less, but the lead conicals provide a higher BC and more "punch".
Ben