GD-116

The GD-116 (Formal designation: 116식 기관 단총 / 一一六式機關短銃, irillyuk-sik gigwan danchong, "Type 116 machine pistol;" Short designation 112식, irillyuk-sik, "Type 116") is a personal defense weapon developed in Menghe in the 2010s. It uses a compact bullpup design, allowing it to achieve an overall length of just 464 millimeters. Innovative features include an ambidextrous forward-ejecting action, a folding bolt handle, MASS slots on the foregrip, and a replaceable bottom section, as well as the option of a 50-round quad-stack magazine.

Within the Menghean armed forces, the GD-116 is currently being issued to helicopter crews, counterterrorism units, and some police forces. There are also plans to phase it in as a general-issue sidearm for tank crews. The External Intelligence Agency is also believed to have obtained a number of examples, for use as a concealed offensive weapon.

Development

The story of the GD-116 begins with the JjS-104DB carbine. An independent design initiative undertaken by Hwasŏng Arsenal 55 in 2010, this consisted of a standard JjS-104 receiver and barrel with re-arranged furniture to form a bullpup weapon. Its short overall length - just 528 millimeters - caught the attention of evaluators in the Ministry of National Defense, who liked the concept of an ultra-compact weapon for vehicle crews or special forces. The JjS-104DB's makeshift implementation, however, ruled it out as a practical option: the safety, fire selector, and magazine release were still next to the user's cheek, and the trigger pull was inconsistent, the result of a bending connection rod between the pistol grip and the sear under the bolt. The location of the charging handle and ejection port also made the weapon impossible to fire left-handed. As such, the MoND opened a design competition for a purpose-built weapon which could surpass the JjS-104DB in dimensions and effectiveness.

Hwasŏng responded most literally with its prototype H33. This was internally almost identical to the successful JS-103, with a long-stroke gas piston and rotating bolt. The rod linking the trigger and sear was improved, incorporating lessons from the SS-110, and similar mechanical links were used to move the fire selector and magazine release to within reach of the pistol grip. The firing handle was relocated to a vertical position under the carry handle to prevent contact with the user's body in any stance or position, and it was made non-reciprocating for good measure. The main selling point of this weapon, compared to the Insŏng proposals, was its ability to accept standard Menghean magazines for 5.7mm Quinn ammunition, a useful feature when issuing the weapon to vehicle crews serving alongside an Army squad.

In a bid to improve its chances, the Insŏng New Arsenal submitted two prototypes. In-15, the more ambitious of the two, used a layout and operation reminiscent of the FN P90, with a horizontal magazine lying flush on top of the receiver and ejecting downward through the buttstock. In a unique embrace of modular design principles, it came with two interchangeable lower sections, one featuring an integral foregrip and one with MASS slots which could be used to mount laser sights, flashlights, and custom foregrips. Though initially promising, the In-15 suffered from a number of practical problems in trials. The spare magazines had a tendency to empty suddenly when struck roughly, and were also known to jam during regular feeding. On the first model, the downward ejection port sometimes threw hot brass onto the back of the user's trigger hand, and even after the addition of a partition to prevent this it was still seen as a liability. On top of these issues, the In-15 also faced the threat of a lawsuit from the Reberiyan company FN Arms, which viewed it as an infringement on the proprietary design features of the P90.

Insŏng's other prototype, the In-14, proved more successful. Despite its more conventional bullpup design, it was slightly shorter than the In-15, and roughly the same height and weight with the magazine removed. Because the Menghean Army favored reliability in a self-defense weapon, its advantages over the In-15 were seen as attractive. The weapon's main disadvantage was the lack of compatibility with the 5.7mm round; the Army had initially pressed for the inclusion of 5.7mm compatibility as a design requirement, but the In-14's simple blowback action and short barrel were not well-suited to such a dramatic increase in propellant. Special forces and counterterrorism units, by contrast, saw the use of a smaller 5.8×21mm round as an advantage, as it allowed an individual to carry more ammunition at a smaller cost in weight and space. Eventually the In-14 won out, earning the official MoND designation GD-116, though the In-15 would still see a limited production run for police and counterterrorism units.

Design

Layout

The GD-116 follows a bullpup configuration with the magazine set behind the pistol grip, a somewhat unique design choice among Septentrion's PDWs and SMGs. It has an overall length of less than half a meter, allowing it to be carried in an under-arm ready sling and quickly brought into action in cramped spaces.

The receiver is divided into upper and lower halves, which are attached to one another with three horizontal captive pins. Both halves use stamped parts to reduce weight and production costs, and the lower section around the pistol grip is made from heat-resistant polymer. A small carry handle over the bolt handle supports a MARS rail, and an indented dust cover sits on the top of the receiver above the action. Interestingly, all variants of the weapon have a fold-down front sight, but the rear sight must be fitted to the rail.

Operation

The GD-116 uses a blowback action, and lacks the gas piston and rotating bolt present on the Hwasŏng H33. It also employs a telescoping bolt which extends over the barrel to reduce the necessary clearance behind the chamber, keeping the weapon compact. The bolt handle is reciprocating, but spring tension keeps it centered under the dust cover when not in use; to charge the bolt the operator reaches over it with one finger, pulls it to either side, and rocks it back. The same system would appear on Insŏng's prototype for the Menghean Army's next-generation rifle.

One of the innovative features of the GD-116 is its typically Menghean brute-force implementation of a forward ejection system. After a round is fired, the spent cartridge casing is ejected upward and forward into the space under the carry handle. There, it strikes an angled panel which deflects it to the right or left. This panel is held in either position by a spring-retained pin, and can be switched from one side to another by manually pressing on its forward tab. On GD-116s purchased by the MoND, a large red glow-in-the-dark arrow is painted on either side of the deflector panel, to provide visual warning: if the arrow is visible, the weapon will eject toward the user's face. In theory the slight angle of the deflector (under 30 degrees from horizontal) ensures that spent casings are thrown forward and to the side, but in practice actual casing paths can grow highly erratic as the weapon heats up.

Another interesting feature of the GD-116 is its solution to the other endemic problem of forward- or downward-ejecting firearms: the difficulty of checking whether a round is in the chamber by pulling back the bolt halfway and looking into the ejection port. Insŏng's solution was to cut three vertical witness holes in either side of the upper receiver, allowing the user to peer in through the side and see the action. When not in use, these can be covered with polymer sliding covers to keep dirt out of the action and protect the user's face.

Ammunition

The GD-116 is typically chambered in 5.8×21mm pistol ammunition, which offers good performance against body armor and allows a larger number of rounds to be carried in the magazine. This does make it less convenient for logistics, as the 5.8mm round is not widely used in the Menghean Army. Additionally, while variants in 9×19mm Parabellum and 7.5×25mm do exist, the GD-116 is not compatible with the overpressure 7.5×25mm +P+ cartridge of the GD-112. With a simple blowback action and polymer covers over holes in the receiver sides, overpressure ammunition could burst during firing and injure the user.

Ammunition is fed from a magazine under the weapon's buttstock. In addition to 30-round magazines, the GD-116 can accept a 50-round quad-stacked casket magazine for the 5.8×21mm cartridge, nearly doubling ammunition capacity for a negligible increase in magazine length. With this magazine inserted, the weapon is 236 millimeters tall.

Users

• Menghe