Weatherby Select 300 Weatherby Magnum 180 grain Interlock Rifle Ammo 20 Bx/ 1. The 300 Weatherby Magnum had the flattest trajectory longest range and the greatest killing power of any 300 magnum on the market until the 30-378 Weatherby Magnum came along. Based on the 300 H&H Magnum the 300 Weatherby delivers 300 more fps than its British cousin. Introduced in 1944 this is the all-around cartridge for the big game hunter. Specifications for Weatherby Select 300 Weatherby Magnum 180 grain Interlock Rifle Ammunition: Manufacturer: Weatherby Caliber: .300 Weatherby Magnum Number of Rounds: 20 Bullet Type: Spitzer Flat Base Bullet Weight: 180 grain Cartridge Case Material: Brass Muzzle Velocity: 3150 ft/s Muzzle Energy: 3967 ft-lbs Application: Medium Game Package Type: Box Included Accessories: None Primer Style: Centerfire Lead Free: No Package Contents: Weatherby Select 300 Weatherby Magnum 180 grain Interlock Rifle Ammunition What is Weatherby Select 300 Weatherby Magnum 180 grain Interlock Rifle Ammunition good for? The manufacturer thinks that it is good for medium game.Weatherby H300180IL: Select 300 Weatherby Magnum 180 grain Interlock Rifle Ammo 20 Bx/