I was right:
The .460 S&W round is a lengthened, more powerful version of the popular .454 Casull, itself a longer and more powerful version of the .45 Colt, which is a longer and more powerful version of the .45 Schofield. Consequently, firearms that fire .460 S&W are usually capable of firing the less powerful .454 Casull, .45 Colt and .45 Schofield rounds, but this must be verified with each firearm's manufacturer. For instance, some lever actions are designed to handle cartridges within a certain length and bullet profile range. The reverse, however, does not apply: .45 Schofield, .45 Colt and .454 Casull handguns generally cannot safely fire .460 S&W rounds—nor can they even chamber the .460 S&W because of the longer case length. The length of the .460 S&W was intended to fully utilize the overall length (2.30") of the S&W X frame cylinder thereby increasing its powder capacity.[citation needed]
The .460 cartridge achieves high velocities by operating at pressures normally reserved for magnum rifle cartridges.