Officially announced in early June 2026, the FN ARKA 5.56x45mm NATO assault rifle expands the defense catalog of the Belgian FN Herstal Group with a new modular individual weapon system developed to compete in the Project Grayburn tender, which will see the UK Ministry of Defence select a successor for the SA-80 bull-pup individual weapon system before 2030.

The FN ARKA is a spin-off of FN's own, highly successful SCAR assault rifle design, but shouldn't be considered as a new generation of the SCAR, or as its replacement: indeed, it is a derivative of the SCAR that capitalizes on the latter's strengths and best selling points while at the same time solving some if its best known drawbacks, chiefly the relatively bulky design for a modern assault rifle and the high cost per unit compared to most competitors.

Like many service rifles developed and launched in the past few years, the FN ARKA is a sleek platform that shares more than a passing similarity with the quintessential AR-15 design and its evolutions, from the M16 rifle to the M4 carbine; unlike many others, however, the FN ARKA isn't based on some derivative of the Stoner working system, opting instead to retain the technical layout of the FN SCAR.

The FN ARKA is thus a gas-operated, short-stroke piston driven firearm featuring a multi-position gas valve to optimize gas management for suppressed operations; a rotating six-locking-lugs bolt is inserted in a single-piece, L-shaped bolt carrier that is basically a slightly shortened variant of the FN SCAR bolt carrier group.

What FN went for, however, is the AR-15s ergonomics and configuration of controls, in order to allow operators who are already familiar with the M16 rifle and M4 carbine to become acquainted with the ARKA much quicker. The FN ARKA thus features a T-shaped AR-15 type charging handle located at the rear of the upper receiver, while the safety/selector switch, magazine catch and bolt hold-open release button are located on the lower receiver, in the same position as on any modern AR-15 variant, and are fully ambidextrous.

The upper and lower receiver are manufactured out of aluminum alloy and held together by front and rear captive pins, so that the FN ARKA field-strips exactly like an M4 carbine; the upper receiver features a full-length top MIL-STD 1913 Picatinny rail for optics and a set of internal steel guides for the bolt carrier group, as well as a forward assist device located just behind the ejection port.

The FN ARKA comes from factory with an AR-15 compatible, removabile pistol grip and an M4 carbine-type collapsible buttstock; the return spring, however, runs within the upper receiver, like in the FN SCAR, instead than within the buffer tube like on any AR-15 variant, thus allowing the use of fully collapsible or side-folding buttstocks in lieu of the factory issued M4-type.

The handguard – featuring a top Picatinny rail and a set of M-LOK slots at 3, 6 and 9-o'clock positions – is a separate component from the upper receiver, and can be removed with a dedicated key; the same tool allows the barrel to be removed (basically like on the FN SCAR), allowing users to change their ARKA's configuration to suit operational needs and requirements at any moment.