This muzzleloader version of the X-Bullet is 100 percent copper with a large, hollow cavity for quick, sure expansion. Barnes' Expander MZ Muzzleloader Bullets produce more consistent shot-to-shot velocities and better accuracy than competing bullets deliver. The result? Greater shooter confidence and more one-shot kills. Expander MZ bullets deliver deadly performance at both high and low velocities. Expand to twice their original diameter, creating six razor-sharp copper petals that slice through game. No fragmentation-these tough, deep-driving bullets typically retain 100 percent of their original weight. Features: 100% Copper Exceptional Accuracy Full weight Retention Razor Sharp Cutting Edges Double-Diameter Expansion Deep Penetration Effective at High and Low Velocities No Fragmentation Recommended for In-Line Riffles Specifications: UPC: 716876451319 Model #: 30569 Caliber : 0.50 Grain : 300 Quantity: 15 - Pack Diameter: .451 S.D.: 0.211 B.C.: 0.207 Length: 1.036 UPC: 716876451265 Model #: 30564 Caliber : 0.50 Grain : 250 Quantity: 15 - Pack Diameter: .451 S.D.: 0.176 B.C.: 0.189 Length: 0.9