The .30-06 Springfield cartridge pronounced “thirty-aught-six” or “thirty-oh-six”, 7.62×63mm in metric notation and called “.30 Gov’t ’06” by Winchester, was introduced to the United States Army in 1906 and later standardized; it remained in use until the early 1980s. The “.30” refers to the caliber of the bullet in inches e.g./ .300 inch, and the “06” refers to the year the cartridge was adopted—1906. It replaced the .30-03, 6mm Lee Navy, and .30-40 Krag cartridges. (The .30-40 Krag is also called the .30 U.S., .30 Army, or .30 Government.) The .30-06 remained the U.S. Army’s primary rifle and machine gun cartridge for nearly 50 years before being replaced by the 7.62×51mm NATO (commercial .308 Winchester) and 5.56×45mm NATO(commercial .223 Remington), both of which remain in current U.S. and NATO service. It remains a very popular sporting round, with ammunition produced by all major manufacturers.
Many European militaries at the turn of the 20th century were in the process of adopting service rounds loaded with pointed spitzer bullets which included 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-grain (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). It was loaded with Military Rifle (MR) 21 propellant and its maximum range was approximately 3,409 yd (3,117 m). 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 resizing the chamber, 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) 1185 propellant and 174-grain (11.3 g) bullet with a 9° boat tail and an ogive of 7 calibers in radius that had a higher ballistic coefficient of roughly 0.494 (G1 BC), 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. Its maximum range was approximately 5,500� yd (5,030 m). 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 was 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 a 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, Caliber .30, Ball, M2 achieved a muzzle velocity of 2,805 ft/s (855 m/s) and muzzle energy of 2,655 ft·lbf (3,600 J). Its maximum range was approximately 3,450 yd (3,150 m).
Performance
The .30-06 cartridge was designed when shots of 1,000 yards (900 m) were expected. In 1906, the original M1906 .30-06 cartridge consisted of a 150 grains (9.7 g), 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, 173 grains (11.2 g) boat-tail, gilding-metal bullet was used. The .30-06 cartridge, with the 173 grains (11.2 g) bullet was called Cartridge, .30, M1 Ball. The .30-06 cartridge was far more powerful than the smaller Japanese 6.5×50mm Arisaka cartridge and comparable to the Japanese 7.7×58mm Arisaka. The new M1 ammunition proved to be significantly more accurate than the M1906 round.
In 1938, the unstained, 9.8 grams (151 gr), flat-base bullet combined with the .30-06 case became the M2 ball cartridge. The M2 Ball specifications required 2,740 feet per second (840 m/s) minimum velocity, measured 78 feet (24 m) from the muzzle.
M2 Ball was the standard-issue ammunition for military rifles and machine guns until it was replaced by the 7.62×51mm NATO round in 1954. For rifle use, M2 Ball ammunition proved to be less accurate than the earlier M1 cartridge; even with match rifles, a target group of 5 inches (130 mm) diameter at 200 yards (180 m) using the 150-grain (9.7 g) M2 bullet was considered optimal, and many rifles performed less well. The U.S. Marine Corps retained stocks of M1 ammunition for use by snipers and trained marksmen throughout the Solomon Islands campaign in the early years of the war.
In an effort to increase accuracy some snipers resorted to use of the heavier .30-06 M2 armor-piercing round, a practice that would re-emerge during the Korean War. Others sought out lots of M2 ammunition produced by Denver Ordnance, which had proved to be more accurate than those produced by other wartime ammunition plants when used for sniping at long range.
With regards to penetration, the M2 ball can penetrate 0.4 in (10.16 mm) of mild steel at 100 yards (91 m), and 0.3 in (7.62 mm) at 200 yards (180 m). M2 AP can penetrate 0.42 in (10.67 mm) of armor steel at 100 yards (91 m). These figures come from army documents. However, a test done by Brass Fetchers shows that M2 AP can actually penetrate up to 0.5in (12.70 mm) of MIL-A-12560 armor steel from a distance of 100 yards (91 m). The round struck the plate at a velocity of 2601 fps, and made a complete penetration.
Commercially manufactured rifles chambered in .30-06 are popular for hunting, current .30-06 factory ammunition varies in bullet weight from 7.1 to 14.3 grams (109.6 to 220.7 gr) in solid bullets, and as low as 3.6 grams (55.6 gr) 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 remains one of the most popular sporting cartridges in the world. Many hunting loads have over 3,000 foot-pounds (4,100 J) of energy at the muzzle and use expanding bullets that can deliver rapid energy transfer to targets.
Some of the information on this page was sourced from Wikipedia
