The .44 Magnum is a large-bore, dual-purpose cartridge designed for revolvers; however it is also used in many rifles as well. It was developed in the mid-1950s by lengthening the .44 Special cartridge and loading it to higher velocities.
The .44 Magnum cartridge was the result of handloading the .44 Special to higher velocities, firing the handloads in weapons that could handle the higher pressures. The .44 Special, and other big bore handgun cartridges were being loaded with heavy bullets pushed at higher than normal velocities for better hunting performance. One of these handloaders was the late Elmer Keith, a famous writer and outdoorsman of the 20th Century.
Elmer Keith settled on the .44 Special cartridge as the basis for his experimentation, rather than the larger .45 Colt. At the time the selection of .44 caliber projectiles for handloaders was better, and the .44 Special case was smaller in diameter than the .45 Colt case—in revolvers of the same size, this meant the .44 caliber revolvers had thicker, and therefore stronger, cylinder walls than the .45. This allowed higher pressures to be used with less risk of a burst cylinder.
Mr. Keith encouraged Smith & Wesson and Remington to produce a commercial version of this new high pressure loading, and revolvers chambered for it. While S&W produced the first prototype revolver chambered in .44 Magnum, the famous Model 29, Sturm-Ruger actually beat S&W to market by several months in 1956 with a .44 Magnum version of the single action Blackhawk revolver. The exact reason for this is lost in legend; one version says a Ruger employee found a cartridge case marked ".44 Remington Magnum" and took it to Bill Ruger, while another says a Remington employee provided Ruger with early samples of the ammunition.
The .44 Magnum case is slightly longer than the .44 Special case, not because of the need for more room for propellant, but to prevent the more powerful cartridge from being chambered in older, weaker .44 Special firearms.
The .44 Magnum was an immediate success, and the direct descendants of the S&W Model 29 and the .44 Magnum Ruger Blackhawks are still in production, and have been joined by numerous other makes and models of .44 Magnum revolvers, and even a few semi-automatic pistols, such as the Desert Eagle. While modern steels and manufacturing techniques have allowed even stronger cylinders, leading to larger and more powerful cartridges such as the .454 Casull, and .480 Ruger, in revolvers the same size as a .44 Magnum, the .44 Magnum is still considered a top choice today. In 2006, to commemorate the 50th anniversary of the .44 Magnum Blackhawk, Ruger introduced a special 50th anniversary Blackhawk revolver, in the original .44 Magnum "Flattop" style.
Despite the ".44" designation, the .44 Magnum and its parent use bullets .429 in (10.9mm) in diameter. A .44 Magnum revolver or rifle will accept both .44 Magnum and .44 Special ammunition, but a weapon designed for .44 Special will only accept the Special, due to the longer overall length of a .44 Magnum cartridge.
The .44 Magnum is a rimmed, centerfire cartridge, usable in both handguns and rifles. It uses a large pistol primer and fires at a maximum pressure of 36,000 PSI, launching a 165 to 355 grain bullet at velocities ranging from around 900 FPS to almost 1900 FPS. The overall length is 1.61 inches and it has a rim diameter of .514 inches.