Editing M1903 Springfield (section)

===World War I and interwar use===
[[File:The US Army on the Western Front 1914-1918 Q70181.jpg|thumb|right|US Marines with M1903 rifles and bayonets in France, 1918]]
[[File:US WWI rifle periscope attachment.jpeg|thumb|An Elder-type [[Periscope rifle|periscope stock]] fitted to an M1903 (1918). Designed for [[trench warfare]], this enabled the shooter to fire over the parapet of a trench while remaining under cover and protected; the rifle is also fitted with a 25-round magazine.<ref name=ordnance332>{{cite journal|title=Bayonet|publisher=U.S. Government Printing Office|journal=Handbook of Ordnance Data|date=15 November 1918|page=[https://archive.org/details/handbookordnanc00unkngoog/page/n348 332]|url=https://archive.org/details/handbookordnanc00unkngoog|format=Digital|oclc=6316176|last1=Ordnance Dept|first1=United States. Army}}</ref>]]
By the time of US entry into [[World War I]], 843,239 M1903 rifles had been produced at Springfield Armory and [[Rock Island Arsenal]]. Pre-war production utilized questionable metallurgy. Some receivers constructed of single-heat-treated case-hardened steel were improperly subjected to excessive temperatures during the forging process, "burning" carbon  out of the steel and producing a brittle receiver.<ref>''Canfield'', February 2008, p. 13</ref> Documented evidence indicates that some early rifles were improperly forged, but actual cases of failure in use were very rare. Several cases of serious injury from receiver failure were documented, but the U.S. Army never reported any fatalities. Many failures were attributed to use of incorrect cartridges, such as the [[7.92×57mm Mauser]].<ref name=l&h>{{cite journal |last1=Canfield |first1=Bruce N. |year=2004 |title=U.S. M1903A1 Rifles |journal=[[American Rifleman]] |volume=152 |issue=January |page=20 }}</ref> Evidence also seems to suggest that improperly forged brass cartridge cases could have further exacerbated receiver failure.<ref>Lyon, Joseph: ''Some Observations On The Failure Of U.S. Model 1903 Rifle Receivers'' [http://m1903.com/03rcvrfail/]</ref>

[[Pyrometer]]s were installed in December 1917 to accurately measure temperatures during the forging process. The change was made at approximately serial number 800,000 for rifles made at Springfield Armory and at serial number 285,507 at Rock Island Arsenal. Lower serial numbers are known as "low-number" M1903 rifles. Higher serial numbers are said to be "double-heat-treated".<ref name=l&h/>

Toward the end of the war, Springfield turned out the Model 1903 Mark I. The Mark I has a cut on the left hand side of the receiver meant to act as an ejection port for the Pedersen device, a specialized insert that replaced the bolt and allowed the user to fire .30 caliber pistol cartridges semi-automatically from a 40-round detachable magazine. The stock was also slightly cut down on the left side to clear the ejection port. In all other respects, the Mark I is identical to the M1903. Temperature control during forging had been improved before Mark I production. The receiver alloy was toughened by addition of nickel after Mark I production.[[File:American First World War Official Exchange Collection Q103350.jpg|thumb|right|Camouflaged M1903 Springfield sniper's rifle with Warner & Swasey [[telescopic sight]] in France, May 1918]]

In 1926, after experiencing the effect of long-range German [[7.92×57mm]] rifle and machine gun fire during the war, the U.S. Army adopted the heavy, 174-grain, [[Boat tail (ballistics)|boat-tail bullet]] for its .30-06 cartridge, standardized as ''Cartridge, Ball, caliber 30, M1''.<ref name="Barnes, Frank C. 1989 p. 59">Barnes, Frank C., ''Cartridges of the World'', 6th ed., DBI Books Inc. (1989), p. 59</ref> M1 ammunition, intended primarily for long-range machine gun use, soon became known by Army rifle competition teams and marksmen for its considerably greater accuracy than the M1906 round; the new M1 ammunition was issued to infantrymen with the Springfield rifle as well as to machine gun teams.<ref>{{cite journal|last=Dunlap|first=Roy|title=Rifles|journal=Ordnance Went up Front: Some Observations and Experiences of a Sergeant of Ordnance, Who Served Throughout World War II with the United States Army in Egypt, the Philippines and Japan, Including Way Stations|date=1948|url=https://books.google.com/books?id=vp8QAQAAMAAJ|oclc=777744849}}</ref> However, during the late 1930s, it became apparent that, with the development of mortars, high-angle artillery, and the .50 caliber [[M2 Browning]] machine gun, the need for extreme long-range, rifle-caliber machine-gun fire was decreasing. In 1938, the US Army reverted to a .30-06 cartridge with a 152-grain flat-base bullet, now termed "[[M2 ball]]", for all rifles and machine guns.<ref name="Barnes, Frank C. 1989 p. 59" />

In the 1920s and the 1930s, M1903s were delivered to US allies in Central America including Cuba, Costa Rica, and Nicaragua. Costa Rican troops were equipped with Springfields during the [[Coto War]], and some rifles were captured by the opposing Panamanians.<ref name="Banana" /> The Cuban Springfields were used by [[Fulgencio Batista|Batista]] forces after WW2 and later by the [[Cuban Revolutionary Armed Forces|Revolutionary Armed Forces]], for instance during the [[Bay of Pigs Invasion]].<ref name="Cuba">{{cite book|title=The Bay of Pigs: Cuba 1961|series = Elite 166|first=Alejandro |last=de Quesada |date=10 Jan 2009|isbn=9781846033230|url=https://books.google.com/books?id=EE-1CwAAQBAJ|page= 60}}</ref>

The [[Federal Bureau of Investigation]] acquired some M1903 rifles configured like [[National Rifle Association]] sporter models in response to the 1933 [[Kansas City Massacre]].<ref>Vanderpool, Bill "Bring Enough Gun" ''[[American Rifleman]]'' October 2013 pp. 80–85&115–116</ref>

In service, the Springfield was generally prized for its reliability and accuracy, though some problems remained. The precision rear aperture sight was located too far from the eye for efficient use, and the narrow, unprotected front sight was both difficult to see in poor light and easily damaged. The Marine Corps issued the Springfield with a sight hood to protect the front sight, along with a thicker front blade. The two-piece firing pin-striker also proved to be no improvement over the original one-piece Mauser design, and was a cause of numerous ordnance repairs, along with occasional reports of jammed magazine followers.<ref name="Dunlap, Roy 1948 p. 302" />