 While one might not be able to easily find ammunition for the big Weatherby or the Nitro Express cartridges, due to its popularity one would be able to find .458 Winchester Magnum cartridges.In an emergency, the .458 Winchester Magnum can be fired in the chamber of a .458 Lott.By 1970 Winchester was forced to deal with the clumping of the compressed powder charge which had been resulting in improper ignition and poor performance.