The cartridge itself has been made in many variants: multiple generations of regular ball, tracer, armor-piercing (AP), incendiary, and saboted sub-caliber penetrator rounds.

The rounds intended for machine guns are made into a continuous ammunition belt using metallic links.

American interest in an armor-piercing cartridge was influenced by the marginal French 11 mm (0.43 in) design, prompting U.S. Army Ordnance officers to consult Browning.

'"[5] The American Rifleman further explains that development was "[r]eputedly influenced by Germany's 13.2x92 mm SR (.525 in) anti-tank rifle" and that then "Ordnance contracted with Winchester to design a .50-cal.

Since the mid-1950s, some armored personnel carriers and utility vehicles have been made to withstand 12.7 mm machine gun fire, restricting the destructive capability of the M2.

It still has more penetrating power than lighter weapons such as general-purpose machine guns, though it is significantly heavier and more cumbersome to transport.

[9] The U.S. Coast Guard uses .50 BMG rifles onboard armed helicopters to disable the engines on boats during interdictions.

[14] Before that, a British sniper in Afghanistan held the record at 2,475 meters (2,707 yd; 1.538 miles) using an Accuracy International AWM L115A3 long-range rifle chambered for .338 Lapua Magnum (8.58×70 mm) rounds.

[15][16] In addition to long-range and anti-materiel, the U.S. military uses .50 BMG weapons to detonate unexploded ordnance from a safe distance.

The round is a scaled-up version of the .30-06 Springfield[citation needed] but uses a case wall with a long taper to facilitate feeding and extraction in various weapons.

While the .50 BMG round is able to deliver accurate shot placement (if match grade ammunition is used) at ranges over 1,000-yard (910 m), smaller-caliber rifles produce better scores and tighter groups in 1,000-yard (910 m) competitions.

[37] A 1999 Justice Department Office of Special Investigations briefing on .50 caliber rifle crime identified several instances of the .50 BMG being involved in criminal activities.

[40] Contrary to a persistent misconception within the United States Armed Forces, using .50 BMG directly against enemy personnel is not prohibited by the laws of war.

[46] Writing for the Marine Corps Gazette, Major Hays Parks states: "No treaty language exists (either generally or specifically) to support a limitation on [the use of .50 BMG] against personnel, and its widespread, longstanding use in this role suggests that such antipersonnel employment is the customary practice of nations."

Parks theorizes that the misconception originated in historical doctrine discouraging the use of the M8C spotting rifle—an integral .50-caliber aiming aid for the M40 recoilless rifle—in the antipersonnel role.