For use with pistols, the .44 Magnum is indeed a high-power round but has also developed a near-mythical reputation due to its being cited by Clint Eastwood playing the title character in the 1971 movie "Dirty Harry":
I know what you're thinking. "Did he fire six shots or only five?" Well, to tell you the truth, in all this excitement I kind of lost track myself. But being as this is a forty-four Magnum, the most powerful handgun in the world, and would blow your head clean off, you've got to ask yourself one question: Do I feel lucky? Well, do ya, punk?
It was introduced in the 1950s. Factory-made 240-grain (3.7 gram) cartridges for the .44 Magnum typically have interor ballistics resulting in 1250 fps muzzle velocity and muzzle energies in the range of 800 ft-lbs. Early cartridges and custom loads would take this to 1400 fps and a muzzle energy in excess of 1200 ft-lbs. By comparison, the .45 ACP, considered a powerful military pistol round, fires a bullet of 165-230 grains, with a muzzle velocity between 845 and 1140 fps.
.44 calibre rounds were introduced by Smith & Wesson in 1869 with the Model No. 3, a top-break handgun, originally chambered for the .44 Henry rimfire, a rifle round. It was not the first pistol to fire a .44 calibre projectile, but the first to use the now familiar method of metallic cartridge cases. Following initial rejection by the U.S. military the round was adapted to centrefire and the .44 American, although retroactively named, was born. Despite the growing popularity of the .45 cartridge the .44 was produced in many differing variants throughout the latter part of the 19th century.
The move to side-swing cyclinders in place of top-break pistols allowed stronger loads to be utilized in handguns which saw the introduction of the .44 Special, a longer cartridge and therefore with more capacity for propellant. Although underutilized at first by manufacturers, the extra capacity allowed experimentation by handloaders, most notably Guns & Ammo author Elmer Keith who wrote about his experiences, encouraging manufacturers to introduce a more powerful handgun cartridge. To overcome fears that a more powerful load might lead to failure in older weapons, Keith suggested that the new cartridge be longer than the .44 Special and therefore only suitable for firing in new, purpose-built handguns, allowing the manufacturers more control on the type of weapon the new cartridge could be used in.
The first to respond to the calls for a more powerful .44 were Smith & Wesson who, together with Remington, began development of the .44 Magnum round in the early 1950's, and in December 1955 Elmer Keith received one of the first .44 Magnum handguns. Around the same time Sturm, Ruger also adapted one of their handguns to fire .44 Magnum rounds and the cartridge was introduced to the public, although it was not until the famous lines by fictional detective Harry Callahan that its modern day popularity began.
It is primarily used for sport, both target shooting with the extra challenge of a high-power weapon, or for hunting. Some big-game hunters use it as an emergency backup to their rifles if surprised at short range, while others may hunt only with the pistol, often employing longer barrels and telescopic sights to enhance range and accuracy. A typical hunting handgun may have a barrel length approaching 10 inches, while a handgun designed for defence would more likely have a barrel length of around 4-6 inches.
Some police officers and a few departments use it for greater stopping power, but that tends to be an individual choice since the weapon is heavier and harder to fire than smaller-caliber weapons. It is not routinely used by any military. Some of the reasons for its choice may be simple machismo.
Modern developments, in both grip shape and material, and in barrel porting, have helped to reduce recoil to more acceptable levels, but for many the .44 Magnum remains too powerful to effectively control. Despite its association with revolvers, the .44 Magnum round can also be used in semi-automatic pistols, where the recoil mechanism can help to further dampen the effects of the powerful round on the user.