KN-3 AO machine gun

The KN-3 served as Astronea's general purpose machine gun (GPMG) for 40 years with distinction. Renowned for its rugged reliability, good ergonomics and suppressive capability, the design saw widespread use throughout the nation's armed forces and its colonies at the time.

In the late 90s, the KN-3 was phased out of front line service, replaced by the newer KN-4 light machine gun. However, a large amount of the machine guns remained in storage, and sale orders for the weapon from former Astronean protectorates showed a continued interest in the KN-3. As a result, a modernized, extended life variant was designed and put into production for export purposes.

The end result, brought into full production in 2003, was a radical improvement over the base KN-3. Gone was the wooden furniture, replaced by polymer parts and rubber. The barrel has been replaced from a quick change to a non field-removable design. The barrel is shorter by a few inches than its parent design, with forced air cooling ribs to ensure the barrel remains cooler when firing, improving reliability.

The main receiver of the KN-3 has also changed drastically. Instead of the stamped lower receiver used on the AM-64, the KN-3AO uses a completely new design, with improved ergonomics, fire selector and trigger mechanism. The upper receiver and feed tray have also been completely altered, moving from a lower ejector to a much higher position in line with the feed tray. While this makes brass eject higher than the KN-3's original design, it improves reliability significantly.

The KN-3 AO also features a new adjustable stock and pistol grip that allow for better mobility and a more comfortable shooting experience. As with all modern upgrades of existing designs, the KN-3AO has a full RIS, with picatinny rail running atop of the feed tray and with options for side mounted laser modules ahead of the hand guard.

Design
The barrel of the KN-3 AO is somewhat heavier than that of the standard KN-3, and has radial cooling ribs. This is enclosed in a steel jacket, which runs up to the muzzle to provide forced air cooling, similar to the distinctive Lewis machine gun designed during the World War I era. Cooling air enters the jacket through oval windows at the rear of the jacket, and exits at the muzzle, propelled by the pressure differential created by the high-velocity gun gases escaping from the muzzle.

Whereas early versions of the AO had a standard KN-3 flash suppressor, resulting in significant muzzle blast once the gun had warmed up, current production version guns have a special flash suppressor that eliminates the issue. The rear of the barrel-encasing steel jacket features a permanently attached carrying handle with a characteristic elongated profile, as it is also intended to protect the line of sight from heat waves generated by convection of air heated up by the barrel.

Another change from the standard KN-3 design is the location of the integral, non-removable folding bipod which is placed near the muzzle. This feature improves stability and long-range accuracy when firing from the bipod

In all other technical respects, such as action and feed, the KN-3 AO is similar to the original design. It also retains the standard mounting interface and can be used from the same tripod.

The use of polymer blending with aluminium and steel keeps the weight of the weapon in check, liberal use of rubber and plastic where available also assists with weight reduction.