Super magnum

A super magnum is a longer version of a magnum handgun cartridge. The most widespread of these calibers are the SuperMag family of super magnums that were proposed and tested by Elgin Gates in the 1970s.

Gates' SuperMags
Gates tested super magnum cartridges in .357, .375, .44, .45, .50, and .60 caliber. Gates' SuperMag cartridges are all 1.610 inches long—about $3/10$ of an inch longer than a standard magnum—and use the same bullets as the original magnum cartridges. The extra powder can increase muzzle velocity up to 30–40% over the original magnum rounds.

In the 1980s, Dan Wesson Firearms began to produce revolvers chambered for the .357, .375, and .445 SuperMag cartridges. In 2000, they added .414 Supermag, and .460 Rowland.

Other super magnums
There have been other cartridges that were created by extending the length of existing magnum cartridges. Some of these are:
 * The .327 Federal Magnum, based on the .32 H&R Magnum
 * The .357 Remington Maximum, based on the .357 Magnum and virtually identical in dimension to the .357 SuperMag
 * The .460 S&W Magnum, based on the .454 Casull. The latter cartridge is effectively, though not in name, a magnum version of the .45 Colt.

.357 SuperMag
Based on the .357 Magnum cartridge, a revolver or single-shot pistol designed for the .357 SuperMag can also fire .357 Magnum, and .38 Special rounds. The .357 SuperMag is essentially the same cartridge as the later-named .357 Remington Maximum that was jointly developed circa 1982-1983 by Sturm, Ruger & Company and Remington, the .357 Max brass being only 0.005" shorter than the .357 SuperMag brass, but identical in all other dimensions. Ruger, as well as Dan Wesson, introduced revolvers in this cartridge, followed shortly later by Thompson/Center in their single-shot Contender.  Due to flame cutting of the top strap of revolvers when shooting cartridges loaded with 125 grain bullets, Ruger discontinued their revolver in this cartridge after a short production run.  Dan Wesson provided a second barrel to customers, but this failed to address customer fears, and the cartridge remained popular only in the T/C Contender.  Remington then dropped this cartridge from production, although brass is still manufactured for reloaders every few years.

.375 SuperMag
Based on the .375 Magnum bullet, this custom round was meant to fit between the .357 and the .445, but is no longer produced. It had a tapered case that was prone to sticking in the cylinder after firing.

.414 SuperMag
Based on the .41 Magnum cartridge.

.445 SuperMag
Based on the .44 Magnum cartridge, a revolver designed for the .445 SuperMag can fire the shorter .44 Magnum, .44 Special, and .44 Russian rounds.