Other Details Manufacturer: Weatherby Manufacturer Part Number: M25792HCB Boxes Per Case: 10 Bullet Type: Hammer Custom Caliber/Gauge: .257 Weatherby Magnum Case Material: Brass Grains: 92 gr Muzzle Energy: 2830 ft lbs Muzzle Velocity (fps): 3570 fps Units per Box: 20 Cost per Round: 5.21