Remington Core-Lokt 264 Winchester Magnum 140gr PSP Rifle Ammo - 20 Rounds - The Remington Core-Lokt bullet design is the original controlled expansion bullet and one of the most effective ever developed. Its progressively tapered copper jacket is locked to a solid lead core, promoting perfectly controlled expansion and high weight retention for dependable hunting results. Reloadable Brass Casings Browse 264 Winchester Magnum Ammo.