The M240 machine gun is officially designated in the United States as the Medium Machine Gun, 7.62 mm, M240. This is the U.S. military designation for the FN MAG, a family of gas-operated, belt-fed medium machine guns in the 7.62 × 51 mm NATO caliber. The M240 has been in service with the U.S. armed forces since the late 1970s. It is widely used by infantry—predominantly in rifle companies—as well as on land vehicles, watercraft, and in aircraft.
Although it is heavier than some comparable machine guns, it enjoys a high reputation due to its reliability. Moreover, its standardization within NATO represents a significant advantage. Now FN America announced at the AUSA 2026 exhibition the new “Tactical Long Rail Upgrade Kit.” The Long-Rail Kit enables the use of modern day and night optics and also offers ergonomic improvements, according to the company at the presentation. The kit is an OEM-developed upgrade for the M240 that adapts its handling to modern optics and deployment scenarios.
Inspired by the recently introduced FN MAG Tactical
For U.S. military units that must keep their in-service M240 weapons ready for modern-day operations by day, night, or with the use of thermal imaging, this kit enables the integration of contemporary sighting systems and configurable ergonomic features. At the same time, the original operating principle as well as the weapon’s proven performance and reliability remain intact. The M240 Tactical Long Rail Upgrade Kit is available for new weapons straight from the factory and as an upgrade for already in-service weapons.
Inspired by the recently introduced FN Herstal model FN MAG Tactical with a long mounting rail (Long Rail), the upgrade kit creates additional usable space for In-Line optics and improves ergonomics, without affecting the handling of the feed cover or the barrel change. Unlike a pure rail-mount, the entire kit is designed to meet the specific requirements for loading, unloading, carrying, aiming, and the overall handling of an optics-equipped machine gun.
“This new upgrade kit allows military units to upgrade their in-service M240 weapons with the latest components. This way they benefit from the weapon’s proven performance while making it ready for today’s combat requirements,” explained Daryl Atkins, Director for Industrialized Weapons at FN America, LLC. “With this kit, modern operators can acquire targets faster, benefit from better ergonomic fitting to the shooter, and use optics more efficiently, while military units preserve and extend the value and relevance of their existing weapon systems.”
Direct feedback from field use with the M240
The MAG, introduced by the U.S. military in 1977, stands among the world’s most proven weapons; since its introduction, more than 100,000 units have been produced. To maximize the performance of this weapon system, FN integrated direct feedback from field use into the development of the Tactical Long Rail Upgrade Kit. The complete set includes:
- A one-piece (monolithic) Picatinny rail (eleven-inch length) for the top, providing about fourteen inches of usable space for in-line optics (day, night, or thermal optics). It enables an optimized eye relief as well as ambidextrous operation of the opening levers, while the original open sight remains usable.
- The FN Side-Click interface on the cover, which enables effortless release from both sides and thus easier one-handed opening.
- The FN Auto-Lock system for locking the cover, which keeps it in the open position during loading, unloading, or clearing jams. The mechanism features an integrated opening stop at 62 degrees to protect the optics and is rated for optics weighing up to 5.5 lbs (about 2.5 kg).
- A long, movable carry handle that facilitates balanced transport and barrel changes even when large inline optics are mounted.
- An adjustable tactical shoulder stock that improves ergonomics and aiming. It offers three length settings, six cheek-rest height positions, an integrated foldable shoulder brace, and an ergonomic butt cap with soft padding.
