.30-06 Springfield - History

History

Many European militaries at the turn of the 20th century were in the process of adopting service rounds loaded with pointed spitzer bullets: France in 1898, Germany in 1905, Russia in 1908, and Britain in 1910, so when it was introduced in 1903, the .30-03 service round loaded with a 220-grain (14 g) round-nose bullet and achieving a muzzle velocity of 2,300 ft/s (700 m/s) was quickly falling behind the ongoing technical evolution.

For these reasons a new case was developed with a slightly shorter neck to fire a spitzer flat-based 150 grains (9.7 g) bullet that had a ballistic coefficient (G1 BC) of approximately 0.405 and achieved a muzzle velocity of 2,700 ft/s (820 m/s) and muzzle energy of 2,428 ft·lbf (3,292 J). The M1903 Springfield rifle, introduced alongside the earlier .30-03 cartridge, was quickly modified to accept the new .30-06 Springfield cartridge, designated by the US military as the M1906. Modifications to the rifle included shortening the barrel at its breech and recutting the chamber. This was so that the shorter ogive of the new bullet would not have to jump too far to reach the rifling. Other changes included elimination of the troublesome 'rod bayonet' of the earlier Springfield rifles.

Experience gained in World War I indicated that other nations' machine guns far outclassed American ones in maximum effective range. Additionally, before the widespread employment of light mortars and artillery, long-range machine gun 'barrage' or indirect fires were considered important in U.S. infantry tactics. For these reasons, in 1926, the Ordnance Corps developed the .30 M1 Ball cartridge loaded with a new Improved Military Rifle (IMR) propellant and 174-grain (11.3 g) bullet with a 9 degree boat tail that had a ballistic coefficient (G1 BC) of approximately 0.560, that achieved a muzzle velocity of 2,640 ft/s (800 m/s) and muzzle energy of 2,692 ft·lbf (3,650 J). This bullet further reduced air resistance in flight resulting in less rapid downrange deceleration, less lateral drift caused by crosswinds, and significantly greater supersonic and maximum effective range from machine guns and rifles alike. Additionally, a gilding metal jacket was developed that all but eliminated the metal fouling that plagued the earlier M1906 cartridge.

Wartime surplus totaled over 2 billion rounds of ammunition. Army regulations called for training use of the oldest ammunition first. As a result, the older .30-06 ammunition was expended for training; stocks of .30 M1 Ball ammunition were allowed to slowly grow until all of the older M1906 ammunition had been fired. By 1936 it was discovered that the maximum range of the .30 M1 Ball ammunition with its boat-tailed spitzer bullets were beyond the safety limitations of many ranges. An emergency order was made to manufacture quantities of ammunition that matched the external ballistics of the earlier M1906 cartridge as soon as possible. A new cartridge was developed in 1938 that was essentially a duplicate of the old M1906 round, but loaded with IMR 4895 propellant and a new flat-based bullet that had gilding metal jacket and a different lead alloy and weighed 152 grains (9.8 g) instead of 150 grains (9.7 g). This 1938 pattern cartridge, the Cartridge .30 M2 Ball achieved a muzzle velocity of 2,805 ft/s (855 m/s) and muzzle energy of 2,655 ft·lbf (3,600 J).