The early 21st century has seen significant advancements in military firearms, particularly in the United States. These ten firearms represent a mix of tradition and innovation in American military history. As conflicts evolve and technology advances, these weapons have adapted to meet the needs of modern warfare, demonstrating the ongoing importance of firearms in military strategy and operations. Whether for infantry, special operations, or long-range engagements, each of these guns has played a significant role in shaping the landscape of 21st-century combat. These guns reflect evolving technology, battlefield requirements, and the changing nature of warfare. Here’s a look at ten notable American military guns from this period.
M4 Carbine
Overview: The M4 Carbine is a versatile, lightweight, air-cooled, gas-operated firearm that has become the standard issue for U.S. military personnel.
Details:
Adoption: Officially adopted in 1994, it has been widely used in conflicts like Iraq and Afghanistan.
Caliber: 5.56×45mm NATO.
Features: A shorter barrel than the M16, with a collapsible stock for better maneuverability in close quarters.

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M16A4 Rifle
Overview: The M16A4 is the latest variant of the M16 series, featuring a flat-top receiver for mounting optics.
Details:
Usage: Used primarily by the Marine Corps and for designated marksman roles.
Caliber: 5.56×45mm NATO.
Features: Equipped with a rail system for accessories, including sights and grenade launchers.

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FN SCAR (Special Operations Forces Combat Assault Rifle)
Overview: Developed for U.S. Special Operations, the FN SCAR is designed for modularity and adaptability.
Details:
Adoption: Gained popularity in special operations units starting in 2004.
Calibers: Available in both 5.56×45mm NATO and 7.62×51mm NATO.
Features: A quick-change barrel system and adjustable stock.

US Army Special Forces
M249 Squad Automatic Weapon (SAW)
Overview: The M249 SAW is a light machine gun that provides infantry squads with sustained fire capability.
Details:
Usage: Heavily utilized in both Iraq and Afghanistan for suppressive fire.
Caliber: 5.56×45mm NATO.
Features: Belt-fed, with a quick-change barrel for rapid fire.

(U.S. Army photo by Spc. Austin Berner / Released)
MK 18 Mod 0
Overview: The MK 18 is a close-quarters weapon developed for Special Operations and maritime environments.
Details:
Usage: Favored by Navy SEALs and other special operations forces.
Caliber: 5.56×45mm NATO.
Features: A compact version of the M4, with a 10.3-inch barrel for improved maneuverability.

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M107 Long Range Sniper Rifle (LRSR)
Overview: The M107 is a .50 caliber sniper rifle designed for anti-material and long-range engagements.
Details:
Adoption: Became operational in the early 2000s, used for engaging vehicles and equipment.
Caliber: .50 BMG (12.7×99mm NATO).
Features: Semi-automatic operation with a heavy barrel for accuracy at long distances.

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XM25 Individual Semi-Automatic Airburst System
Overview: The XM25 is an innovative weapon designed to engage enemies behind cover with airbursting grenades.
Details:
Development: Initially fielded for testing in 2010, aimed at increasing effectiveness in urban combat.
Caliber: 25mm.
Features: Includes a computerized sighting system that allows the user to program the grenade’s detonation.

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M14 Rifle
Overview: Although originally adopted in the 1950s, the M14 saw a resurgence in the early 21st century as a designated marksman rifle.
Details:
Usage: Some units in Iraq and Afghanistan utilized modified M14s for long-range engagements.
Caliber: 7.62×51mm NATO.
Features: Known for its accuracy and range, it utilizes a semi-automatic action.

U.S. Army
SIG Sauer P320
Overview: The P320 is a modular handgun that became the U.S. Army’s sidearm after the Modular Handgun System competition.
Details:
Adoption: Officially adopted in 2017 as the M17 and M18 models.
Caliber: 9mm Parabellum.
Features: A modular design that allows users to change grip sizes and calibers easily.

DAVE CHAN | Credit: AFP via Getty Images
M240 Machine Gun
Overview: The M240 is a general-purpose machine gun known for its reliability and versatility.
Details:
Usage: Widely used by U.S. forces in various conflicts, appreciated for its durability in harsh conditions.
Caliber: 7.62×51mm NATO.
Features: Belt-fed, capable of being mounted on vehicles or used as a ground weapon.

Markus Rauchenberger | Credit: U.S. Army