Other Details Manufacturer: Weatherby Manufacturer Part Number: M280A139HCB Boxes Per Case: 10 Bullet Type: Hammer Custom Caliber/Gauge: .280 Ackley Improved Grains: 139 gr Muzzle Energy: 2871 ft lbs Muzzle Velocity (fps): 3050 fps Units per Box: 20 Cost per Round: 3.80