Munmu Z620
| Munmu Z620 Assault Rifle Series | |
|---|---|
 Possible variants of the Munmu Z620 series. | |
| Type | assault rifle Light machine gun |
| Place of origin |  Zhenia |
| Service history | |
| In service | 1965 to Present |
| Used by | see "Users" |
| Production history | |
| Designer | Munmu Arsenal |
| Designed | 1956-1964 |
| Manufacturer | Munmu Arsenal (later Munmu Industries) |
| Produced | 1965-Present |
| No. built | 10,000,000+ |
| Variants | see below |
| Specifications | |
| Weight | AR: 3.8 kg (8.38 lb) Carbine: 3.56 lb (1.61 kg) PDW: 3.2 kg (7.05 lb) LMG: 4.98 kg (10.98 lb) |
| Length | AR: 998 mm (39.3 in) Carbine: 908 mm (35.7 in) PDW: 764 mm (30.1 in) LMG: 1,080 mm (43 in) |
| Barrel length | Carbine: 656 mm (25.8 in) (stock folded) PDW: 636 mm (25.0 in) (stock collapsed) |
| Cartridge | 6.8 mm Munmu |
| Action | AR, Carbine, PDW: Gas-operated, rotating bolt |
| Rate of fire | 700-900 RPM (AR, Carbine, PDW) 700-1000 RPM (LMG) |
| Muzzle velocity | 900 m/s |
| Effective firing range | 200-1000 m |
| Feed system | AR, Carbine, PDW: 10, 30, or 40-round detachable box magazine or 100-round drum magazine LMG: 30 or 40-round detachable box magazine or ammunition belt |
| Sights | Adjustable iron sights |
The Munmu Z620 is a series of Zhenian assault rifles and derived light machine guns designed and produced by Munmu Arsenal (later Munmu Industries). Although originally intended to be a highly modular weapon, it only shares some common parts between the rifle and light machine gun variants, deviating from the original intention of the design. It was most commonly used as the service rifle of the Greater Eastern Union Defense Forces since the 1960s; although it was later superseded by the Z2000 rifle line as the primary service rifle, it remains in service in many reservist units and foreign armies.
Development
Shortly after the Coup of 1955, the Greater Eastern Union Army issued a demand for a new assault rifle that would replace the existing Z450 rifles in service and altogether be standardized across all military units in the nation, as well as an automatic rifle capable of providing effective fire support when needed. Such line of new rifles would continue the tradition from the Z450 to be chambered in the Munmu 6.8mm rounds while also retain full-automatic fire capability to provide enough firepower should the need ever arise. The two demands, originally anticipated to become two separate projects, became one bigger project altogether when it had been decided that the automatic rifle demand was swapped with a light machine gun that can provide effective, automatic suppression fire on the frontline, and that such rifle would be based on the assault rifle to save development costs and training time. With the initial objective of the rifle's introduction to initiate around 1962, its development was originally dubbed the Type 62 common infantry weapon.
The initial plan behind the series that would later become the Z620 was to build it into a completely modular rifle, with the adjustment and addition of modular parts allowing direct, on-site conversion into any of the variants excluding the PDW variant. While the modular rifle idea became an inspiration for later projects decades later, it had been scrapped during the development of the Z620 series, abandoning the direct, on-site conversion capability between the assault rifle variants and the light machine gun, although a degree of parts commonality has been achieved. During the development process, long-stroke gas-operated rotating bolt mechanism, among other possible options, were decided as the primary operation mechanism for the inside works of the assault rifle; a press manufacturing method was chosen for the primary building method of the rifle to simplify and ease the manufacturing process.
Although its introduction into frontline military service was somewhat later than planned, its first prototypes rolled out in 1962, around the original planned date. With minor refinements in areas such as the iron sights and room for a side rail for additional optics in the future, the first production models saw frontline service at the Greater Eastern Union Army in 1965, both the assault rifles and light machine guns; the Greater Eastern Union Marine Corps received the assault rifles, alongside a revised version of the light machine gun that was a lot closer to the assault rifles, a year later.