Nevertheless, the weapon was exported internationally and has found usage in militaries around the world, notably in armies in Mexico and Singapore.

On March 27, 2008, the United States Marine Corps issued a Purchase Description outlining the requirements for the Infantry Automatic Rifle (IAR) to potential manufacturers.

The rifle therefore never saw widespread usage in the U.S. Military but was released to the civilian market in 2017, albeit at a very low quantity at only 200 units by the U.S. Armament Company.

[1][6] In 2010, the Colt IAR6940 was selected and sold to the Naval Infantry Corps of the Mexican Navy and is widely used in the ongoing drug war in Mexico.

[7] In 2023, Ministry of Defense Singapore performed trials[8] for the New Section Automatic Weapon (NSAW) program, which would replace the aging Ultimax 100 which has been in use for roughly 42 years.

[9] The new Light Machine Gun, the IAR6940E-SG, is a new variant of the Colt IAR that was evaluated and procured in partnership with the Defence Science and Technology Agency and has been assessed to be a suitable successor to the Ultimax 100.

[10] It was introduced to the Singapore Army on April 24, 2024,[11] and fully replaced the Ultimax 100 on the end of July 2024, as troops underwent more training on the Colt IAR6940.

The gas developed from the fired cartridge is vented directly towards the bolt, sending it rearward to cycle the action.

[15][17][18] Other characteristics of the upper receiver are largely similar to that of the M4/M16-type rifles, like the forward assist, cartridge deflector, and ejection port cover.

[1][15] A large heat sink is implemented on the lower hand guard, which is aimed to increase the time it takes for the firearm to cook-off under extended periods of fire due to overheating.