KN-3

The KN-3 is a general-purpose machine gun designed in 1960 with the purpose of augmenting the squad fire-support role from heavier tripod mounted machine guns to a man-portable system that could be operated by one soldier.

The KN-3 was replaced by the KN-3 AO in 1993 as the main general purpose machine gun of Astronea's Armed Forces. However, it still sees use in the Astronean Republican Guard paramilitary force and reserves. In terms of use, the KN-3 is incredibly widespread, known for its sustainable firerate, accuracy at range and reliable performance in extreme conditions. The KN-3 is generally quite light when compared to other GPMGs, while still firing a heavy duty round capable of penetrating surfaces such as sheet metal and wood.

It features a quick change barrel for swapping out barrels when they overheat, as well as a carry handle for ease of maneuvering. Informally, this also allows the weapon to be effectively fired from the hip, albeit in short bursts, in situations where a soldier must lay down fire while on the move.

The KN-3 is sold in both 7.62x51mm and 7.62x54mm for export purposes.

Design
The KN-3 machine gun series is an open bolt design, which improves heat management during automatic fire compared to closed bolt designs and helps avoiding the dangerous phenomenon known as "cook-off", wherein the firing chamber becomes so hot that the propellant contained in a chambered round unintentionally ignites, making to weapon fire until the ammunition is exhausted. Open bolt designs typically operate much cooler than closed bolt designs due to the airflow allowed into the chamber, action and barrel during pauses between bursts, making them more suitable for constant full-automatic weapons such as machine guns. The KN-3 is normally issued with several quick change barrels that during prolonged intensive use are swapped out allowing one barrel to cool while the machine gun fires with the other.

The breech is locked by a rotating bolt, with two locking lugs engaging locking recesses in the receiver. The gas piston is hinged lo the bolt carrier assembly, and its vertical travel makes it possible to bend the group making machine gun assembly and disassembly for maintenance easier. The protruding rear part of the bolt carrier assembly features spiral shaped cuts, which provide a controlled rotation of the bolt. The mainspring is accommodated in the bolt carrier assembly slide channel. A cartridge extractor with a latch is mounted in the rear part of the bolt carrier assembly. The cocking lever, mounted on the right, is not integral with the bolt carrier and does not reciprocate as the gun fires. The machine gun fires from the rear sear.

The gas cylinder is mounted under the barrel and fitted with a gas regulator with three fixed positions. The gas regulator opens corresponding holes to change the amount of expanding propellant gases bled off out of the gas cylinder into the atmosphere, thus varying the amount of energy transferred on to the long-stroke piston. Receiver

The trigger assembly, mounted inside the receiver, is operated by the mainspring and suitable for automatic fire. It has no single shot mode. The manual rotating type safety locks the sear, which engages the sear notch of the bolt carrier assembly, and the trigger lug does not allow the bolt earner assembly to go all the way back

KN-3T
The KN-3T variant is a modified KN-3 for mounting on coaxial positions of armoured vehicles. In this configuration the trigger assembly is replaced with an electric solenoid trigger, the bipod, carry handle and stock are removed and a heavier and longer barrel is used. Typically 250 round belts are used and the KN-3T fitted with a gas regulator.

The KN-3T has been mounted on main battle tanks, infantry fighting vehicles and armoured personnel carriers in various formats, both alongside the barrel and on top-mounted machine-gun positions above commander hatches. More modern systems integrate the KN-3T into remote-weapon systems with a remote-controlled 360° turret and a digital camera.

KN-3 AO
A modernised, extended life variant designed for export purposes, now in service as the primary GPMG of Astronea. Bbrought into full production in 2003, the KN-3 AO a radical improvement over the base KN-3. 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 AO version also inegrates a piccatiny system for the mounting of optics and illumination devices.

The KN-3AO is expected to serve with the AAF for the foreseeable future.