The .500 S&W Magnum (12.7×41mmSR) is a fifty-caliber semi-rimmed handgun cartridge developed by Cor-Bon in partnership with the Smith & Wesson “X-Gun” engineering team for use in the Smith & Wesson Model 500 X-frame revolver and introduced in February 2003 at the SHOT show. Its primary design purpose was as a hunting handgun cartridge capable of taking all North American game species.
The .500 S&W Magnum is a semi-rimmed, straight cartridge optimized for use in revolvers. The cartridge is designed to headspace on its rim. However, unlike rimmed cartridges such as the .44 Magnum and other cartridges designed for use in revolvers, the cartridge can be cycled more smoothly and more reliably in tubular or magazine rifles, due to the semi-rimmed design.
The .500 S&W Magnum was designed to fire a bullet with a diameter of .500 in (12.7 mm) unlike the .500 Linebaugh, which fires a .510 in (12.9 mm) bullet. This was done so as not to run afoul of the National Firearms Act and be considered a Destructive Device as had happened to Whildin’s .50 AE cartridge, which at first was designed to fire a .510 in (12.9 mm) but had to be redesigned to fire a .500 in (12.7 mm) instead.
The .500 S&W Magnum is considered the most powerful commercial sporting handgun cartridge by virtue of the muzzle energy it can generate. Cor-Bon (now a Dakota Ammo brand) who together with Smith & Wesson developed the .500 S&W Magnum cartridge, offers several loads which include a 325 gr (21.1 g) at 1,800 ft/s (550 m/s), a 400 gr (26 g) at 1,625 ft/s (495 m/s) and a 440 gr (29 g) at 1,625 ft/s (495 m/s). Compared to the next most powerful commercial sporting handgun cartridge, the .460 S&W Magnum, which can launch a 325 gr (21.1 g) at 1,650 ft/s (500 m/s) or a 395 gr (25.6 g) at 1,525 ft/s (465 m/s), the .500 S&W Magnum produces about 15% to 40% more muzzle energy than the .460 S&W. The .500 S&W Magnum comes into its own when used with heavier bullets, particularly those with weights of 500 gr (32 g) or greater. When possible these bullets should be seated as far out as possible to take advantage of the complete cylinder length, so as to maximize the powder capacity which the case can provide.