RE: which dead center bullet for my disc rifle?
Knight rifle barrels are overbore in comparison to CVA, Traditions, Remington, Thompson, Winchester, Austin-Halleck... etc.
In my opinion, Knight, Hornady & Barnes sabot bullets perform best in your rifle because of their thicker-designed plastic sabots. I don't understand/comprehend why Cecil Epp over at Precision Bullet Co has not introduced a bullet package designed specifically for Knight & White overbore rifles. Powerbelt Inc was the first to introduce this concept.... others should follow suit as well.
There are situations where some Knights will shoot Precision sabot/bullet combos well, but to the best of my knowledge -- from what I've read on blackpowder/muzzleloading forum homes across this country -- those Knights that do shoot Precision bullets well at 100 yards & beyond are of the minority... not majority.