As far as weapon systems are concerned, having the best available can be key to success on the battlefield.
But with rapid changes in technology, some weapons come and go rather quickly. Other times, weapons are so well designed and so effective, they stay in service for decades.
Here are 10 of the longest-serving weapons ever used by the United States military.
1. M1903 Springfield .30 Cal Rifle
U.S. Marines with M1903 rifles and bayonets in WWI France, 1918. (Imperial War Museum photo)
The M1903 was one of the first rifles to use the famous .30-06 round and was the standard American infantry rifle during World War I. Although officially replaced by the M1 Garand in 1937, it was still in service due to insufficient numbers of Garands. The Springfield .30 cal was retained as a sniper rifle through the Korean War and even into Vietnam before finally being retired after over 60 years of service.
2. M1911 .45 Cal Pistol
A U.S. Marine with the 26th Marine Expeditionary Unit's maritime raid force fires an M1911 .45 caliber pistol at a range in Jordan during Eager Lion 2013. (U.S. Marine Corps photo)
The M1911 is a creation of the legendary gunmaker John Browning, and it endured in service for over 100 years. The pistol became an icon for its strength in battle and by those who used it. The M1911 was phased out in favor of the Beretta M9 9mm pistol in the late 1980s but has stayed in service with Marine Special Operations units and is now designated as the M45.
3. M1919 .30 Cal Machine Gun
A Navy machine gunner of the Riverine Force in Vietnam using an M1919 being fed by an upside-down M-13 link belt. (DoD photo)
The M1919 was another one of John Browning's successes. An air-cooled version of the M1917 that served U.S. troops well in World War I, it saw extensive use in World War II and Korea. The M1919 was phased out in favor of the new M60 in the late 1950s. However, the Navy, having a surplus of the weapons, converted many to 7.62 mm and used them on gun boats patrolling the rivers of Vietnam.
4. M2 .50 Cal Machine Gun
LCpl. Paul Rodas mans a .50 caliber machine gun as part of the security force during an exercise in the Central Command AOR. The 24th MEU is on their six-month deployment in support of Operation Enduring Freedom. (U.S. Navy Photograph by PH2(SW) Michael Sandberg)
The "Ma Deuce" is a weapon system loved by the troops who use it and feared by those it targeted. The gun was designed near the end of World War I, too late to see service, and entered full production in 1921. Also designed by John Browning, the weapon is so well-built that in 2015 a 94 year old example was found still in service. Though numerous other designs have been proposed, the military has no plans to stop using the M2 anytime soon.
5. B-52 Stratofortress
Munitions on display show the full capabilities of the B-52 Stratofortress. (U.S. Air Force photo by Tech. Sgt. Robert J. Horstman)
The B-52 was designed to deliver nuclear weapons against the Soviet Union during the height of the Cold War. Despite never having to conduct this mission, the B-52 has been the workhorse of conventional bombing campaigns for more the 60 years. The Air Force plans to keep it in service into the 2040s.
6. M60 .30 Cal Machine Gun
Staff Sgt. Clarence Neitzel of the 173d Airborne Brigade mans an M60 machine gun on Hill 875 outside of Dak To on November 22, 1967. (U.S. Army photo)
The M60 entered service in 1957, just in time to see heavy use in the jungles of Vietnam. The M60 served as the standard machine gun for the U.S. military until the 1990s when the M240 was adopted. However, more than 50 years later, the M60 continues to serve with some SEAL teams and as helicopter armament.
7. M14 .30 Cal Rifle
Gunner's Mate 1st Class Marcus Wrice fires an M14 rifle during a weapons qualification aboard the Nimitz-class aircraft carrier USS Carl Vinson. (U.S. Navy photo by Mass Communication Specialist Seaman Nicolas C. Lopez)
The M14 had a short service life as the standard American infantry rifle from 1959 to 1964 when it was replaced by the M16. But the rifle never left service and was the basis for the M21 and M25 sniper rifles before making a serious comeback during the Global War on Terror when it was upgraded to the M14 Enhanced Battle Rifle.
8. M16 5.56 mm Rifle/ M4 Carbine
Sergeant Christopher L. Mc Cabe fires his rifle during monthly range training on May 15, 2008. (U.S. Marine Corps photo by Cpl. Thomas J. Griffith)
Since replacing the M14 in 1964, the M16/M4 family of rifles has become the longest-serving standard rifle for the U.S. military. Despite its troubled beginning, the M16 and M4 have earned a hard-fought reputation as reliable and effective weapons. Despite numerous attempts to replace it, no competition has yielded a better rifle.
9. LGM-30 Minuteman Ballistic Missile
An unarmed LGM-30G Minuteman III intercontinental ballistic missile launches during an operational test Feb. 20, 2016, at Vandenberg Air Force Base, Calif. (U.S. Air Force photo by Senior Airman Kyla Gifford)
The Minuteman intercontinental ballistic missile has served as part of the U.S. nuclear triad since entering service in 1962. The Minuteman was the first ICBM to employ multiple independent reentry vehicles, allowing each missile to deploy three separate warheads for greater chances of target destruction. The Air Force, responsible for the missiles, currently operates 450, down from the peak of 1,000 during the 1970s.
10. M61 Vulcan 20 mm Cannon
An AC-130A Spectre gunship's 20mm Vulcan cannon ammo belt. This is the earlier belted M61. (U.S. Air Force photo)
The M61 is the United States' primary armament for fixed-wing aviation. After entering service in 1959, the gun saw extensive use in Vietnam by all branches fighting in the skies. The gun was credited with shooting down 39 MiGs during the war. After over 50 years of service, the M61 is still found on American fighters and in the Navy's Phalanx CIWS.