Shoot a box of Remington Core-Lokt .300 Winchester Magnum 150 Grain Centerfire Rifle Ammo to see why it has remained the leader in hunting ammunition for more than six decades. Core-Lokt ammo uses one of the most effective hunting bullets ever developed - the original controlled-expansion bullet design. A progressively tapered copper jacket is locked to a solid lead core to promote a perfectly controlled expansion and high weight retention after impact. Remington Core-Lokt Centerfire Rifle Ammo uses only premium brass cases, primers, and powders that you can rely on in any hunting environment. Proven big game hunting ammunition The original controlled-expansion bullet design Progressively tapered copper jacket Jacket locked to a solid lead core Controlled expansion and high weight retention Premium brass cases, primers, and powders