Editing .30-06 Springfield (section)

==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 {{convert|220|gr|adj=on}} round-nose bullet. Around 1901, the U.S. started developing an experimental rimless cartridge for a Mauser action with a box magazine. That led to the 1903 [[.30-03 Springfield]] rimless service round that used the same {{convert|220|gr|adj=on}} round-nose bullet as the Krag.<ref name="Sharpe591">{{cite book |last=Sharpe |first=Philip B. |title=The Rifle in America |date=1938 |publisher=William Morrow |quote=The rimless cartridge case first used a standard 220-grain Krag bullet, but in 1906 the government decided that high velocity was necessary and accordingly adopted the German form of pointed or spitzer bullet, reducing the weight to 150 grains closely approximating the 154-grain 8&nbsp;mm Mauser. |page=591}}</ref> The .30-03 achieved a muzzle velocity of {{convert|2300|ft/s|m/s|abbr=on}}.{{Citation needed|date=January 2021}}

Many European militaries at the beginning of the 20th century were adopting lighter-weight (roughly {{convert|150|to|200|gr|adj=on}}), higher velocity, service rounds with [[spitzer (bullet)|pointed (spitzer) bullets]]: France in 1898 ([[8×50mmR Lebel]] ''Balle D'' spitzer {{convert|198|gr|g}} with [[boat-tail bullet|boat-tail]]), Germany in 1903 ([[7.92×57mm Mauser]] {{convert|153|gr|g}} ''S Patrone''), Russia in 1908 ([[7.62×54mmR]] ''Lyokhkaya pulya'' [light bullet]), and Britain in 1910 ([[.303 British#Mark VII|.303 British Mark VII]] {{convert|174|gr|g}}).<ref>{{cite web |url=http://www.303british.com/id19.html |title=Cartridge Specifications and Chronology |access-date=26 October 2014}}</ref> Consequently, the round-nosed U.S. [[.30-03]] service cartridge was falling behind.<ref>{{cite web |url=http://www.m1-garand-rifle.com/30-06/ |title=The .30-06 Springfield Cartridge |work=The M1 Garand Rifle |access-date=26 October 2014}}</ref>

===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 {{convert|150|gr|2|adj=on}} bullet that had a [[ballistic coefficient]] (G1 BC) of approximately 0.405, a muzzle velocity of {{convert|2700|ft/s|m/s|abbr=on}}, and a muzzle energy of {{Convert|2429|ftlbf|J|abbr=on}}. The cartridge was loaded with military rifle (MR) 21 propellant, and its maximum range was claimed (falsely) to be {{convert|4700|yd|m|-1|abbr=on}}.<ref>{{cite book |last=Hatcher |first=Julian S. |author-link=Julian Hatcher |date=1962 |title=Hatcher's Notebook |edition=3rd |publisher=Stackpole Company |location=Harrisburg, PA |lccn=62-12654 |page=19 |quote=The maximum range was given in the handbooks as 4700 yards.}}</ref> 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 the elimination of the troublesome "rod bayonet" of the earlier Springfield rifles.{{Citation needed|date=January 2021}}

The M1906 maximum range was originally overstated. When the M1906 cartridge was developed, the range tests had been done to only {{convert|1800|yd|m|-1}}; distances beyond that were estimated, but the estimate for extreme range was incorrect by almost 40 percent.<ref>{{harvnb|Hatcher|1962|p=20}}<!-- Hatcher says 38 percent: 3400 yd actual * 1.38 = 4692 yd would match 4700 yd claim--></ref> 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 fire]]s were considered important in U.S. infantry tactics.<ref>{{cite book |last=George |first=John |title=Shots Fired in Anger |publisher=NRA Press |date=1981 |pages=402–403}}</ref> 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.<ref>{{harvnb|Hatcher|1962|pp=21&ndash;23}}</ref> 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 {{convert|3300|to|3400|yd|m|-1}}.<ref>{{harvnb|Hatcher|1962|pp=19&ndash;20}}</ref> Germany, which was using the ''S Patrone'' (S ball cartridge) loaded with a similar {{convert|153|gr|g|adj=on}} 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 {{convert|197.5|gr|g|2|adj=on}} ''s.S. – schweres Spitzgeschoß'' (heavy spitzer) boat-tail bullet which had a maximum range of approximately {{convert|5000|m|yd|0|abbr=on}}.<ref name="S and s.S. Patrone ballistics 2">{{Cite web |url=http://pdf.textfiles.com/manuals/FIREARMS/fn_fn98.pdf |title=FN Mauser Model 98 rifle and carbine operator's manual}}</ref>

===.30 M1 ball cartridge===
For these reasons, in 1926, the ordnance corps, after extensive testing of [[7.5×55mm Swiss#The GP 11 cartridge|7.5×55mm Swiss GP11]] projectiles provided by the Swiss, developed the .30 M1 ball cartridge loaded with a new [[Improved military rifle powder|improved military rifle (IMR) 1185]] propellant and {{convert|174|gr|2|adj=on}} bullet with a 9° boat-tail and an [[ogive]] of 7 [[Calibre length|calibers]] [[nose cone design|nose cone]] that had a higher [[ballistic coefficient]] of roughly 0.494 (G1 BC),<ref>{{cite web |url=https://www.snipercentral.com/m118.phtml |title=M118 History - Sniper Central |access-date=26 October 2014}}</ref><ref>{{cite web |url=http://www.cruffler.com/trivia-July99.html |title=Firearm Technical Trivia, July 1999 |first=Adam C. |last=Firestone |website=www.cruffler.com}}</ref> that achieved a muzzle velocity of {{convert|2647|ft/s|m/s|abbr=on}} and muzzle energy of {{Convert|2675|ftlbf|J|abbr=on}}.<ref name="Hatcher 1962 29">{{harvnb|Hatcher|1962|p=29}}</ref> 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.<ref name="cgsc.edu">[http://www.cgsc.edu/carl/docrepository/FM23_10.pdf FM 23-10 ''Basic Field Manual: U.S. Rifle Caliber .30, M1903'', 20 September 1943 page 212] {{webarchive |url=https://web.archive.org/web/20130418083932/http://www.cgsc.edu/carl/docrepository/FM23_10.pdf |date=April 18, 2013 }}</ref> Additionally, a [[gilding metal]] jacket was developed that all but eliminated the metal fouling that plagued the earlier M1906 cartridge.
The loaded round weighed {{convert|420|gr}} and its maximum range was approximately {{convert|5500|yd|m|-1|abbr=on}}.<ref name="cgsc.edu"/> The maximum average pressure (MAP) was {{convert|48000|psi|MPa|2|abbr=on}}. The average target radius was specified to be not greater than {{convert|4.5|in|cm|0|abbr=on}} at {{convert|500|yd|m|0|abbr=on}} and not greater than {{convert|5.5|in|cm|0|abbr=on}} at {{convert|600|yd|m|0|abbr=on}} when fired from a Mann accuracy weapon.<ref name="auto">{{Cite web |url=https://books.google.com/books?id=msoIAQAAIAAJ&q=m2+link+.50&pg=PA9 |title=Technical Manual Small-Arms Ammunition, TM9-1990, U.S. War Department |access-date=20 February 2020 |date=23 May 1942}}</ref><ref>{{Cite web |url=http://www.odcmp.org/1001/mann_inc.asp |title=The CMP Mann Accuracy Devices |last1=Rutledge |first1=Steven T. |date=2001-07-27 |access-date=2023-02-11 |website=odcmp.org}}</ref>

===Cartridge, caliber .30, ball, M2===
Wartime surplus totaled over two 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 [[Improved military rifle powder#IMR #4895|IMR 4895]] propellant and a new flat-based bullet that had a gilding metal jacket and a different lead alloy, and weighed {{convert|152|gr|2}} instead of {{convert|150|gr|2}}. This 1938 pattern cartridge, the cartridge, caliber .30, ball, M2, achieved a muzzle velocity of {{convert|2805|ft/s|m/s|abbr=on}} and muzzle energy of {{Convert|2656|ftlbf|J|abbr=on}}.<ref name="Hatcher 1962 29"/> The loaded round weighed {{convert|416|gr}} and its maximum range was approximately {{convert|3450|yd|m|-1|abbr=on}}.<ref name="cgsc.edu"/> The MAP was {{convert|50000|psi|MPa|2|abbr=on}} by copper crusher (equivalent to the SAAMI CUP unit). The average target radius was specified to be not greater than {{convert|6.5|in|cm|1|abbr=on}} at {{convert|500|yd|m|0|abbr=on}} and not greater than {{convert|7.5|in|cm|1|abbr=on}} at {{convert|600|yd|m|0|abbr=on}}.<ref name="auto"/>