.30-06 Springfield

The .30-06 Springfield cartridge (pronounced "thirty-aught-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 late-1970s. The ".30" refers to the caliber of the bullet in inches. 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 .30-06 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 and 5.56×45mm NATO, 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.
History.
In the early-1890s, the U.S. military adopted the smokeless powder .30-40 Krag rimmed cartridge. The 1894 version of that cartridge used a round-nose bullet. Around 1901, the U.S. started developing an experimental rimless cartridge for a Mauser action with box magazine. That led to the 1903 .30-03 rimless service round that used the same round-nose bullet as the Krag. The .30-03 achieved a muzzle velocity of .
Many European militaries at the beginning of the 20th century were adopting lighter-weight (roughly ), higher velocity, service rounds with pointed (spitzer) bullets: France in 1898 (8mm Lebel "Balle D" spitzer with boat-tail), Germany in 1903 (7.92×57mm Mauser "S Patrone"), Russia in 1908 (7.62×54mmR "Lyokhkaya pulya" [light bullet]), and Britain in 1910 (.303 British Mark VII ). Consequently, the round-nosed U.S. .30-03 service cartridge was falling behind.
Cartridge, ball, caliber .30, Model of 1906 (M1906).
For these reasons, the U.S. military developed a new, lighter cartridge in 1906, the .30-06 Springfield, "cartridge, ball, caliber .30, Model of 1906", or just "M1906". The .30-03 case was modified to have a slightly shorter neck to fire a spitzer flat-based bullet that had a ballistic coefficient (G1 BC) of approximately 0.405, a muzzle velocity of , and a muzzle energy of . The cartridge was loaded with military rifle (MR) 21 propellant, and its maximum range was claimed (falsely) to be . The M1903 Springfield rifle, which had been introduced alongside the .30-03 cartridge, was modified to accept the new .30-06 Springfield cartridge. Modifications to the rifle included shortening the barrel at its breech and resizing the chamber, so that the more tapered bullet would not have to jump too far to reach the rifling. Other changes to the rifle included elimination of the troublesome "rod bayonet" of the earlier Springfield rifles.
The M1906 maximum range was originally overstated. When the M1906 cartridge was developed, the range tests had been done to only ; distances beyond that were estimated, but the estimate for extreme range was wrong by almost 40 percent. The range discrepancy became evident during World War I. 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. When the U.S. entered World War I, it did not have many machine guns, so it acquired British and French machine guns. When those weapons were later replaced with U.S. machine guns firing the M1906 round, the effective range of the barrage was 50 percent less. Firing tests performed around 1918 at Borden Brook Reservoir (Massachusetts), Miami, and Daytona Beach showed the actual maximum range of the M1906 cartridge to be . Germany, which was using the "S Patrone" (S ball cartridge) loaded with a similar flat-based bullet in its rifles, had apparently confronted and solved the same problem by developing an aerodynamically more refined bullet for long range machine gun use. The "s.S. Patrone" was introduced in 1914 and used a "s.S. – schweres Spitzgeschoß" (heavy spitzer) boat-tail bullet which had a maximum range of approximately .
.30 M1 ball cartridge.
For these reasons, in 1926, the ordnance corps, after extensive testing of 7.5×55mm Swiss GP11 projectiles provided by the Swiss, developed the .30 M1 ball cartridge loaded with a new improved military rifle (IMR) 1185 propellant and bullet with a 9° boat-tail and an ogive of 7 calibers nose cone that had a higher ballistic coefficient of roughly 0.494 (G1 BC), that achieved a muzzle velocity of and muzzle energy of . 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.
The round weighed and its maximum range was approximately . The maximum average pressure (MAP) was . The average target radius was specified to be not greater than at and not greater than at when fired from a Mann accuracy weapon.
Cartridge, caliber .30, ball, M2.
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 military firing 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 instead of . This 1938 pattern cartridge, the cartridge, caliber .30, ball, M2, achieved a muzzle velocity of and muzzle energy of . The round weighed and its maximum range was approximately . The MAP was . The average target radius was specified to be not greater than at and not greater than at .
Firearms.
In military service, the .30-06 was used in the bolt-action M1903 Springfield rifle, the bolt-action M1917 Enfield rifle, the semi-automatic M1 Garand rifle, the semi-automatic M1941 Johnson rifle, the Famage Mauser, the Browning Automatic Rifle (BAR), and numerous machine guns, including the M1917 and M1919 series. It served the United States in both World Wars and in the Korean war, its last major use was during the Vietnam war.
The Belgian army (ABL) bought the FN Model 1949 rifle in .30-06 calibre (both as a sniper version with telescopic sights and as a general service weapon). The Belgium armed forces used the round widely in the Korean war, where the .30-06 calibre FN-49 proved to be a superior weapon in terms of both accuracy and reliability to the American M1 Garand. The .30-06 FN-49 saw widespread use in the various wars in and around the Belgian Congo. The 30-06 FN-49 was also sold to the armies of Luxembourg, Indonesia and Colombia. Another customer was Brazil where it served the navy.
Large volumes of surplus brass made it the basis for dozens of commercial and wildcat cartridges, as well as being extensively used for reloading. In 1908 the Model 1895 Winchester lever-action rifle became the first commercially-produced sporting rifle chambered in .30-06 Springfield. It is still a very common round for hunting and is suitable for large game such as bison, Sambar deer, and bear, when used at close to medium ranges.
In 1903, the Army converted its M1900 Gatling guns in .30 Army to fit the new .30-03 cartridge as the M1903. The later M1903-'06 was an M1903 converted to .30-06. This conversion was principally carried out at the Army's Springfield Armory arsenal repair shops. All models of Gatling guns were declared obsolete by the U.S. Army in 1911, after 45 years of service.
Ballistically, the .30-06 is one of the most versatile cartridges ever designed. With "hot" handloads and a rifle capable of handling them, the .30-06 is capable of performance rivaling many "magnum" cartridges. However, when loaded more closely to the original government specs, .30-06 remains within the upper limit of felt recoil most shooters consider "tolerable" over multiple rounds, unlike the magnums, and is not unnecessarily destructive of meat on game such as deer. With appropriate loads, it is suitable for any small or large heavy game found in North America. The .30-06's power and versatility (combined with the availability of surplus firearms chambered for it and demand for commercial ammunition) have kept the round as one of the most popular for hunting in North America.
Performance.
The .30-06 cartridge was designed when shots of were expected. In 1906, the original M1906 .30-06 cartridge consisted of a , flat-base cupronickel-jacketed-bullet. After World War I, the U.S. military needed better long-range performance machine guns. Based on weapons performance reports from Europe, a streamlined, boattail, gilding-metal bullet was used. The .30-06 cartridge, with the 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, , flat-base bullet combined with the .30-06 case became the M2 ball cartridge. The M2 ball specifications required minimum velocity, measured 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 diameter at using the M2 bullet was considered optimal, and many rifles did not perform nearly as 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 re-emerged 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 AP round can penetrate at least of armor steel at . A test done by Brass Fetchers shows that M2 AP can actually penetrate up to of MIL-A-12560 armor steel from a distance of . 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 in solid bullets, and as low as 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 of energy at the muzzle and use expanding bullets that can deliver rapid energy transfer to targets.
The table above shows typical muzzle velocities available in commercial 30-06 loads along with maximum .30-06 muzzle velocities reported by several reloading manuals for common bullet weights. Hodgdon, Nosler, and Barnes report velocities for barrels. Hornady and Speer report velocities for barrels. The data are all for barrels with a twist rate of 1 turn in which is needed to stabilize the heaviest bullets. The higher muzzle velocities reported by Nosler for and heavier bullets use loads employing a slow-burning, double-base powder (Alliant Reloder 22).
The newer 7.62×51mm NATO/.308 Winchester cartridge offers similar performance to standard military .30-06 loadings in a smaller cartridge. However, the greater cartridge capacity of the .30-06 allows much more powerful loadings if the shooter desires.
Recoil.
One reason that the .30-06 has remained a popular round for so long is that the cartridge is at the upper limit of power that is tolerable to most shooters. Recoil energy (free recoil) greater than will cause most shooters to develop a serious flinch, and the recoil energy of an rifle firing a 30-06 bullet at is . Recoil-shy shooters can opt for lighter bullets, such as a bullet. In the same rifle, a bullet at will only generate of recoil energy. Young shooters can start out with even lighter bullets weighing .
Cartridge dimensions.
The .30-06 Springfield cartridge case can hold of water and has a volume of . 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.
Americans defined the shoulder angle at alpha/2 = 17.5 degrees. According to the "Commission Internationale Permanente pour l'Epreuve des Armes à Feu Portatives" (C.I.P.) the common rifling twist rate for this cartridge is 254 mm (1 in 10 in), 4 grooves, Ø lands = 7.62 mm (.30 in), Ø grooves = 7.82 mm (.308 in), land width = 4.49 mm (.1768 in) and the primer type is large rifle.
According to the official C.I.P. 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 combination has to be proofed at 125% of this maximum C.I.P. pressure to certify for sale to consumers. The 8×64mm S is the closest European ballistic twin of the .30-06 Springfield.
Military cartridge types.
"Note:" .30-06 cartridges are produced commercially with many different bullets and to a number of different specifications.
United States.
The .30-06 round was replaced by the 7.62×51mm NATO round in 1954. However, it remained in limited use in the army reserves and national guard for some time; Frankford Arsenal only stopped production in 1961 and Lake City Army Ammunition Plant was making .30-06 until the late 1970s, with new production batches in 1993 and 2002.
Commonwealth.
The .30-06 (or "caliber .30") cartridge was adopted in 1940 during the beginnings of the Lend-Lease program in anticipation of using American weapons in front-line service. The British used American-made ammunition during the war, which was designated as "cartridge S.A, .30" to avoid confusing it with their own .303 British service round. It was used after the war as belted machinegun ammunition by the Royal Armored Corps and was not declared obsolete until October, 1993. The "z" after the numeral indicates that it used a nitrocellulose propellant rather than cordite. Marks of ammunition were originally designated with Roman numerals (i.e., .303 Ball Mark VII), but were replaced with Arabic numerals by 1945 (i.e., .303 Ball MK 7).
French Union.
The .30-06 round was adopted in 1949 for use in American war surplus military aid weapons like the M1 Garand and M1919 medium machinegun. Military production was from the 1950s to the mid-1960s, while export production to French Union nations lasted until the late 1980s. Cartridge cases were softer than US specifications to prohibit their being recovered and reloaded by insurgents. 