The .30 Carbine (7.62x33mm) is the cartridge used in the M1 Carbine introduced in the 1940s. It is an intermediate round designed to be fired from the M1 carbine's 18-inch (458 mm) barrel.
The .30 Carbine cartridge and the M1 Carbine were developed by Winchester and the U.S. Army to provide assault troops and rear area units more firepower and accuracy than the standard issue M1911A1 .45 ACP caliber handgun and .45 Thompson submachine gun. The weapon was originally issued with a straight 15-round detachable magazine. The cartridge itself is basically a rimless .308 caliber (7.62 mm) version of the much older .32 Winchester Self-Loading cartridge of 1906. The propellant was much newer, though, taking advantage of chemistry advances. The cartridge's relatively straight case and the rounded nose of its bullet led some to believe it was designed for use in pistols.
The M1 Carbine was issued to infantry officers, machine gun, artillery and tank crews, paratroopers and other line-of-communications personnel in lieu of the larger, heavier M1 Garand. The Carbine and its reduced-power .30 cartridge was not intended to serve as a primary infantry weapon, nor was it comparable to more powerful intermediate cartridges later developed for assault rifles.
The M1 Carbine and the later M2 Carbine continued in service during the Korean War. The M2 Carbine featured a selective-fire switch allowing optional fully-automatic fire at a rather high rate (850–900 rpm) and a 30-round magazine. A postwar U.S. Army evaluation reported on the weapon's cold-weather shortcomings, and noted complaints of failure to stop heavily-clothed North Korean and Chinese troops at close range after multiple hits. However, the carbine was again issued to some U.S. troops in Vietnam, particularly reconnaissance units (LRRP) and advisors as a substitute standard weapon. Reports of the ineffective stopping power of the .30 Carbine in close combat continued through the rest of its U.S. service.
In 1994, Israel introduced the Magal, a compact weapon based on the Galil MAR using the .30 Carbine cartridge. After complaints of overheating and other malfunctions, the Magal was withdrawn from service in 2001. The M1 Carbine is still issued to the Israel Police and Civil Guard.
U.S. Army specifications for the new cartridge mandated the caliber to be greater than .27, with an effective range of 300 yards or more, and a midrange trajectory ordinate of 18 inches or less at 300 yards. With these requirements in hand, Winchester's Edwin Pugsley choose to design the cartridge with a .30 caliber, 100-120 grain bullet at a velocity of 2000 feet per second. The first cartridges were made by turning down rims on .32SL cases and loading with .308 caliber bullets sharing a similar profile as the the U.S. military .45 ACP bullet. The first 100,000 cartridges manufactured were headstamped ".30 SL".
The popularity of the M1 Carbine for collecting, sporting, and re-enactment use has resulted in continued civilian popularity of the .30 Carbine cartridge. For hunting, it is considered a small-game cartridge, of marginal power for deer-size game. Even in long-barreled carbines, military-style full metal jacket projectiles do not expand, causing little tissue damage. In addition, the high sectional density of the projectile causes the bullet to overpenetrate. Soft-point and hollowpoint cartridges are considered to be more effective, but are offered by only a few manufacturers.
A number of handguns have been chambered for .30 Carbine ammunition. In 1944, Smith & Wesson developed a hand-ejector revolver to fire .30 Carbine. It went through 1,232 rounds without incident. From a four-inch (102 mm) barrel, it launched the standard GI ball projectile at 1,277 ft/s (389 m/s), producing a large average group of 4.18 inches (106 mm) at 25 yards (23 m). The loud blast is the most oft-mentioned characteristic of the .30 M1 Carbine cartridge fired in a handgun.
In 1958, the short-lived J. Kimball Arms Co. produced a .30 Carbine caliber pistol that closely resembled a slightly scaled-up High Standard Field King .22 target pistol. The Ruger Blackhawk revolver chambered for the .30 Carbine round has been in the catalogs since the late 1960s. Standard government-issue rounds clock over 1,500 feet per second (460 m/s), with factory loads and handloads producing similar velocities. Other handguns chambered for this cartridge include the Thompson Center Contender, Ruger Blackhawk, and the AMT AutoMag III.
A standard .30 caliber ball round weighs 110 grains (7.1 g) m and has a muzzle velocity of 1,900 ft/s (580 m/s) giving it 880 foot-pounds (1,190 joules) of energy. By comparison, a .357 Magnum revolver fires the same weight bullet from a 4 inch barrel at about 1,500 ft/s for about 550 foot-pounds of energy, though it is important to note that the .357 bullet is larger in diameter (caliber) and is normally an expanding or hollow-point design.