Weatherby Select .340 Weatherby Magnum 250 Grain Rifle Ammo 20 Rounds. However Roy took advantage of the longer case to pack in more powder for greater velocity. And it shoots heavier 338 bullets at higher velocities as well ? a decidedly powerful combination. Ideally suited for animals the size of elk or larger the 340 can also be used by deer hunters with lighter bullet weights. Specifications for Weatherby Select .340 Weatherby Magnum 250 Grain Rifle Ammunition: Manufacturer: Weatherby Caliber: .340 Weatherby Magnum Number of Rounds: 20 Bullet Weight: 250 grain Application: Deer Package Type: Box Included Accessories: None Primer Style: Centerfire Fabric/Material: Brass Gun Type: Rifle Package Contents: Weatherby Select Hornady Interlock Rifle Ammuntion .340 Wby Mag 250gr 2963 fps What is Weatherby Select .340 Weatherby Magnum 250 Grain Rifle Ammunition good for? The manufacturer suggests that it is good for deer.Weatherby H340250IL: Select .340 Weatherby Magnum 250 Grain Rifle Ammo 20 Rounds