.30-06 Springfield
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Image:Ammo 30cal belt 1942.jpg
Naval ordnance men loading a belt of .30-06 into an SBD Dauntless.
The .30-06 Springfield cartridge (pronounced “thirty-aught-six” or "thirty-oh-six") is a 7.62 mm (.308in.) calibre rifle cartridge , or 7.62x63mm, introduced to the United States Army in 1906 (hence “06”) and standardized, used until 1960s and early 1970s. It was developed from and superseded the nearly identical .30-03, having a slightly shorter casing and a higher velocity spitzer bullet. There were three main production runs of the round, that roughly correspond to large stocks built up during wars: the initial .30-06, the M1 Ball, and the M2 Ball. The M1903 Springfield rifle, introduced alongside the earlier cartridge, was quickly modified to accept the .30-06. It replaced the 6 mm Lee Navy as well as remaining older calibers such as the .30 US Army (also called .30-40 Krag) used in the Model 1892 Krag. The .30-06 remained the US Army's main cartridge for nearly 50 years before it was finally replaced by the 7.62 x 51 mm (7.62mm NATO, commercial .308 Winchester) with the adoption of the M14 in 1954. However, the first M14s were not fielded until 1957, and the .30-06 remained in service into the 1970s, mainly as a machine gun cartridge. It was used in the bolt-action M1903 Springfield rifle, the semi-automatic M1 Garand, the Browning Automatic Rifle (BAR), and numerous machine guns, including the M1919 series. It served the United States in both World Wars and in the Korean War, its last major use being in Vietnam. Large volumes of surplus brass made it the basis for dozens of commercial and wildcat cartridges, as well as being extensively used for reloading. The .30-06's power, combined with the ready availability of surplus firearms chambered for it, and so demand for commercial ammunition, has made it a popular hunting round. It is suitable for large mammals such as deer, elk, and moose.
PerformanceThe .30-06 is a powerful cartridge designed when 1.0 km (1100 yards) shots were expected. In 1906, the original .30-06 cartridge consisted of a 9.7 g (150 grain), flat-base cupronickel-jacketed-bullet. After WWI, the U.S. military needed better long range performance machine guns. Based on weapons performance reports from Europe, a streamlined, 11.2 g (173 grain), boat tail, gilding-metal bullet was used. The .30-06 cartridge, with the 11.2 g bullet was called the "M1 Ball". Army practice was to use the oldest ammunition for training, so old stocks of M1906 were used until 1936. Once the new M1 began to be used, the military saw it went past the safety limits of firing ranges built for the 1906 cartridge in the previous thirty years. Rather than rebuild, the military returned to the original profile bullet, but utilising a new jacket. Initially, it was stained to match the cupro-nickel jacket. In 1940, this unstained, 9.8 g (152 grain), flat-base bullet became the standard "Ball, M2" cartridge. According to U.S. Army Technical Manual 43-0001-27, M2 Ball specifications require 835 m/s (2,740 feet per second) velocity, measured 24 m (78 feet) from the muzzle. M2 Ball was the standard issue ammunition for military rifles and machineguns until replaced by the 7.62x51mm for the M14 and M60. Commercially manufactured rifles chambered in .30-06 are popular for hunting. Current .30-06 factory ammunition varies in bullet weight from 7.1 g to 14.3 g (110 to 220 grains) in solid bullets, and as low as 3.6 g (55 grains) with the use of a sub-caliber bullet in a sabot. Loads are available with reduced velocity and pressure as well as increased velocity and pressure for stronger firearms. The .30-06 ranks as one of the most popular sporting cartridges in the world. There is a new cartridge that delivers the same ballistics as the 30-06. The 30 tc ; a short but powerful cartridge. See thompson center arms for details. Cartridge dimensionsThe .30-06 Springfield has 4.43 ml (68.2 grains) H2O cartridge case capacity. The exterior shape of the case was designed to promote reliable case feeding and extraction in bolt action rifles and machine guns alike, under extreme conditions. .30-06 Springfield maximum C.I.P. cartridge dimensions. All sizes in millimeters (mm). Americans would define the shoulder angle at alpha/2 = 17.5 degrees. The common rifling twist rate for this cartridge is 254 mm (1 in 10 in), 4 grooves, Ø lands = 7.62 mm, Ø grooves = 7.82 mm, land width = 4.49 mm and the primer type is large rifle. According to the official C.I.P. (Commission Internationale Permanente pour l'Epreuve des Armes à Feu Portatives) guidelines the .30-06 Springfield case can handle up to 405 MPa (58,740 psi) piezo pressure. In C.I.P. regulated countries every rifle cartridge combo has to be proofed at 125% of this maximum C.I.P. pressure to certify for sale to consumers. The .30-06 Springfield is a Delta L problem cartridge, meaning it can present unexpected chambering and/or feeding problems. The Delta L problem article explains this problem in more detail. The 8x64mm S is probably the closest European ballistic twin of the .30-06 Springfield. The 8x64mm S was intended as a ballistic upgrade option for the Mauser Gewehr 98 rifles that were then standard issue in the German military. The German military chose however to stick to their 8x57mm IS rifle cartridge avoiding rechambering their service rifles for a larger and heavier cartridge.
.30-06 Springfield cartridge dimensions. All sizes in inches (in). U.S. military cartridge typesNOTE: .30-06 cartridges are also produced commercially with a plethora of different bullets and to a number of different specifications.
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