Originally developed by FN Herstal in the late 1950s and now in service in numerous configurations with more than 90 nations – including the US, where it is known as the M240 – the FN MAG in 7.62x51mm NATO remains one of the most widely fielded and combat-proven machine guns of its class. Designed for users who need to modernize existing inventories without replacing a trusted platform, the latest Tactical version preserves the weapon’s core mechanical performance while addressing the operational needs of modern soldiers. At the heart of the upgrade is the Long Rail Conversion Kit, designed to provide true in-line dual optic capability for day optics, night-vision devices, and thermal imagers. This allows the gunner to use modern sighting systems without compromising the weapon’s original function or battlefield reliability.
FN MAG Tactical video introduction
FN MAG Tactical with Long Rail – New features
The new top cover integrates an 11” Picatinny rail, providing approximately 14 inches of usable operational space space. This makes it possible to mount full-size in-line day, night or thermal optic combos with an optimized eye relief, while still retaining the use of the original iron sights. The cover also features FN’s fully ambidextrous Side-Click feed cover opening system, allowing the latch to be operated easily from either side of the gun.
For safer and more efficient handling, the FN Auto-Lock feed cover retention mechanism holds the feed cover open during loading, unloading, and clearing procedures. A built-in 62-degree opening stop / raised-angle limitation system helps protect mounted optics, while still allowing the cover to support up to 2.5 kg of optical equipment.
Another key component is the articulated carrying handle, which maintains balanced carry and allows barrel changes even with mounted optics. This is a critical feature for sustained-fire roles, where rapid barrel replacement remains essential. The modified handle also compensates for the change in the weapon’s center of gravity when optics are fitted.
The telescoping tactical buttstock further improves shooter interface. Adjustable for both length of pull and cheek height, it offers three length positions and six cheek-rest settings. The stock also incorporates a folding shoulder rest and a soft butt plate.
A major advantage of the FN MAG Tactical with Long Rail is its broad compatibility. The upgrade can be applied not only to FN MAG guns, but also to related configurations such as the M240 family in U.S. service and the L7A2 in British service. It is available with new weapon orders or as a separate retrofit kit that unit armorers or technicians can install quickly with basic tools. The tactical buttstock is also offered as a stand-alone upgrade.
