The 450 Bushmaster was designed as a close-range, big-bore hunting caliber for the AR-15 platform. As with most AR cartridge conversions, it only requires swapping out the upper receiver. With the introduction of some new bolt-action rifles in this caliber and many states changing game laws allowing straight-wall cartridges for deer hunting, the .450 Bushmaster is enjoying a surge in popularity. Ruger now offers their American Ranch and Gunsite Scout bolt-action rifles chambered in the .450 Bushmaster caliber. This cartridge utilizes the common .452″ diameter bullet; reloaders can use bullet weights anywhere from 160–350+ grains.