The Barnes Triple-Shock X-Bullets in 9.3mm (.366 caliber) deliver revolutionary hunting performance with 100% copper construction and 286 grain weight in a reliable flat base design.Barnes Triple-Shock X-Bullets - 9.3mm (.366 diameter)286 grain flat base bullet design100% copper construction for superior performanceExpands on impact creating four razor-sharp cutting petalsRetains 100% of original weight for maximum penetrationPenetrates dense bone and tissue effectively50 bullets per boxOptimal seating depth: 0.03 to 0.07 inches off riflingEngineered for hunters who demand one-shot kills on big game these bullets provide exceptional accuracy and devastating terminal performance with deep cutting capability and reliable expansion.