The MX is a 6.5mm assault rifle used as a standard-issue weapon for the BLUFOR army. It is lightweight, reliable, easily serviceable and compatible with a large number of accessories. Several variants of the MX rifle exist: MX 3GL is equipped with a 3GL grenade launcher. MXM is a designated marksman rifle for engaging targets from a larger distance compared to assault rifles. MX SW is a light support weapon providing light machinegun support. And finally MXC is a carbine version with shorter barrel, better suited for close quarters combat.
The MX series are a family of service weapons used by both NATO forces and CTRG operators in ArmA 3.
The MX family was designed by real-life gun manufacturer CMMG Inc. of Missouri, U.S.A, specifically for ArmA 3.
Its design appears to be inspired by two real-world rifles, most notably the Remington "ACR" and Robinson Armament's "XCR-L" assault rifles.
Co-incidentally, both weapons were a part of failed tenders designed to be replacements for multiple service weapons in the U.S. military.
On the other hand, the MX's underbarrel grenade launcher is directly based on the real-world "3GL" grenade launcher designed by the (now-defunct) Australia-based weapons manufacturer MetalStorm.
Despite firing caseless 6.5 mm ammunition, an ejection port is present on all variants.
During ArmA 3's pre-Alpha phase, early media releases did not show either the MX or its sub-variants being used by NATO forces. Sand/tan-coloured versions of the Mk20 bullpup were used as stand-in placeholders instead.
Curiously, the MXM variant was also presumably meant to have been chambered to fire 7.62 mm caseless ammunition instead of the standard 6.5 mm cartridge used by the other MX variants.
This can be seen via an unused icon that is still accessible in the game files (texture name: m_20rnd_762x51_caseless_ca.paa) that depicts the same digital camouflage, straight-box magazine used by regular MX variants, but is wider-shaped, flatter, and is also only designed to hold 20 rounds as opposed to 30.
No config references or leftover text strings for this variant remain however, which suggests that the 7.62 mm-chambered MXM was scrapped early in development.
Prior to the release of the Marksmen DLC, the MX SW featured a non-functional integrated bipod that was unfolded by default during the Alpha.
It was later changed so that the bipod was folded, and was eventually removed entirely as the weapon was re-factored to accept regular bipods on its underbarrel rail (the integrated bipod would become a standalone attachment for NATO forces that could be used by all compatible weapons).
The black and khaki variants of the MX were not initially included upon ArmA 3's release. The black variants were added in Game Update 1.08 as part of the AAF Reinforcements Pack, while the khaki versions were not added until the release of the Apex DLC.