From T/C:

 T/C’s Mag Express Sabots are designed to be used with jacketed or lead pistol bullets. Mag Express Sabots load easily, and are designed to separate from the projectile quickly. This rapid separation means superior accuracy, as the projectile is influenced less by the “drag” of the sabot, while on its way to the target. T/C’s Mag Express Sabots are available preassembled with XTP™ bullets, known for their tremendous expansion, or as loose sabots, ready for custom loading. They offer superior performance with conventional charges, or magnum charges of up to 150 grains of black powder or Pyrodex® equivalent (or 3 Pyrodex® Pellets). When using T/C’s Mag Express Sabots behind magnum charges, the hunter can extend his range out to 200 yards.