Type 39 submachine gun

Type 39 submachine gun
File:Type 39 SMG.png Type 39 prototypes and variants
Type	submachine gun
Place of origin	Menghe
Service history
In service	1940–1970s
Production history
Designer	Insŏng Arsenal
Designed	1939
Manufacturer	numerous
Produced	1939-1945
Specifications
Weight	3.47 kg (7.65 lb)
Length	Type 39: 844mm Type 39 compact: 592mm (stock folded)
Barrel length	268mm including muzzle brake
Cartridge	7.5×25mm Menghean
Action	blowback, open bolt
Rate of fire	500 rounds per minute
Muzzle velocity	500 m/s
Effective firing range	200-300m
Feed system	40-round magazine
Sights	Iron sights

The Type 39 submachine gun (Menghean: 39식 기관단총 / 三九式機關短銃, sam-gu-sik gigwandanchong, literally "three-nine-type machine pistol") is a submachine gun designed in the Greater Menghean Empire during the Pan-Septentrion War. It was also license-produced in Dayashina as the Type 99 submachine gun (九九式機関短銃, kyū-kyū-shiki kikan-tanjū).

Background

During the interwar era, the Menghean armed forces paid little attention to the development of SMGs. The Federal, later Imperial, Army believed that Menghe's wars would be highly mobile engagements fought at long ranges in the plains and mountains, where accurate rifle fire mattered most; submachine guns would remain useless in most engagements. Menghe also faced the problem of how to adequately equip its large Army and Navy from a limited industrial base, and its procurement officers determined that the cost, production time, and high ammunition consumption of SMGs were better spent on increasing rifle production.

Working on their own time, some of Menghe's state arsenals conducted design studies and built prototype SMGs, but none of these were adopted for mass production. In fact, police units repeatedly looked abroad for procurement orders, importing MP 18 and MP 28 SMGs from Ostland.

With the beginning of the Pan-Septentrion War in the Hemithean theatre, the Imperial Menghean Army was still without a standard service SMG, though the Imperial Navy had procured some MP 28s for its amphibious Marine Infantry. During initial fighting against Sylva and Maverica, which also lacked SMGs during this period, the Menghean focus on rifles and carbines proved adequate, and for a few years this upheld the Army's view that close-range, high-rate-of-fire weapons were superfluous.

Two main developments changed this approach. The first was the assault on Khalistan and Portcullia in late 1938. Marine Infantry assault squads armed with MP 28s proved invaluable at clearing trenches, bunkers, and coastal settlements, areas where the long Type 17 rifle often proved awkward and clumsy. MP 18s in mainland police service were even confiscated and shipped down to equip Army units fighting Tyrannian commandos holed up in Portcullia's mountains. The second development was the arrival of Rajian expeditionary volunteer units in Themiclesia. Some of these volunteer were armed with KP/-31s, the first SMGs Menghean forces had encountered in an opposing force on any significant scale. In the absence of Navy assault units, the Army's advance slowed, and officers reported back that even in relatively open terrain SMGs were a real threat.

Development

In need of an SMG of their own, the Imperial Menghean Army commissioned a design competition in January 1939, inviting Menghe's state arsenals and private workshops to contribute prototypes for evaluation. Jŏng Sŭng-yong, the designer of the Type 17 rifle, submitted a design, though his rising partner Ha Dong-u did most of the actual design work. The initial prototype was chambered in Ostlandian 9×19mm Parabellum ammunition and had a distinct straight magazine, though it was soon switched to the 7.5x25mm cartridge, also a product of the Insŏng Arsenal where Jŏng and Ha worked.

Rather than copying the KP/-31, as some other entries did, Jŏng and Ha looked to imported MP 18s for inspiration. The resulting weapon would share a number of traits with its Ostlandian predecessors, including the trigger group, the disassembly method, and the shape of the bolt. Jŏng and Ha did implement several of their own improvements, however, including a fixed firing pin to simplify the bolt assembly and a downward-facing magazine to improve balance. They also took steps to lighten the weapon, removing the barrel shroud and slightly thinning certain parts, with the aim of conserving steel and allowing easy transport.

While it did not excel at its tests, the Jŏng/Ha prototype performed adequately, and was better than any of its readily available competitors. All in all, it was a respectable weapon for a country that had not produced an independent SMG until then, and future upgrades and supplements would improve on its basic form. The Army approved it for production in the year 1939, and the first deliveries to service units took place around the beginning of 1940.

Design

The Type 39 follows what would later become a very conventional submachine gun configuration, with wooden furniture behind and a box magazine projecting downward ahead of the trigger. It fires from an open bolt, allowing the use of a fixed firing pin and a minimalistic safety system, and uses a simple blowback action with no locking or delay features. The recoil spring is contained entirely within the receiver, and the charging handle reciprocates when the weapon is fired. Early-production models featured a muzzle brake / compensator on the end of the barrel with two upward-facing notches, intended to reduce recoil and counteract muzzle climb.

The Type 39 is chambered in the Menghean 7.5×25mm pistol cartridge. Compared with 9mm pistol and SMG rounds, the 7.5×25 had poor stopping power at close distances but a somewhat flatter trajectory at range, reflecting the Imperial Menghean Army's lasting focus on long-range capability in small arms. Also illustrative is the adjustable tangent iron sight, which is instrumented out to an optimistic range of 800 meters. Later variants would replace this with a simple L-shaped adjustable aperture sight. The Type 39 fires from a 40-round box magazine with a slight curve to accommodate the 7.5×25mm cartridge's taper. These magazines are double-stack but single-feed, a design choice which allowed a simpler bolt design but made them difficult to reload in the field.

The most notable characteristic of the Type 39 is its almost spartan simplicity, part of Jŏng's characteristic imperative to minimize the number of moving parts. It has no semi-automatic fire mode, though the rate of fire is low enough that the operator can tap off individual rounds with a brief squeeze of the trigger. It also has no safety lever. Instead, the operator safes the weapon by pulling back the charging handle and lifting it up at the end of its travel path, allowing it to slide forward into a notch that holds it in place. The bolt can also be left in the forward, uncocked position with no round in the chamber. This approach was borrowed directly from the MP 18, and allowed for modest savings in training, production, and maintenance.

Disassembly of the Type 39 is very straightforward, and very similar to disassembly of the MP 18. With the bolt forward and the magazine removed, the operator rotates a lever at the end of the receiver, allowing the receiver and barrel to pivot upward on a pin behind the magazine well. The operator can then unscrew the receiver's end cap, which is knurled for an easy grip, and remove the recoil spring, which is still under tension. With the receiver pivoted upward, a new travel path for the charging handle is exposed, allowing the operator to easily slide out the entire bolt and handle in one piece. This results in only three moving parts apart from the hinged receiver-and-handguard assembly, which can be separated if the captive pin is slid out but are usually kept together for regular field maintenance. The open configuration also allows easy access to the trigger assembly, which, like that on the MP 18, is very straighforward.

Curiously for a weapon so heavily simplified, the receiver was machined rather than stamped. This drove up production time, required more steel, and resulted in a heavier weapon. Indeed, successors to the Type 39 would use stamped components wherever possible. The reasoning behind this construction was that Menghe's existing heavy-duty stamping facilities were already running at capacity, while a simple milled tube would be easy to produce using a cylindrical blank and a lathe. This would allow the Army to rapidly put its new SMG into mass-production, and later on it would allow village workshops to produce their own further-simplified models.

A very small number of early-production Type 39s - probably fewer than 1000 in all - were fitted with an under-barrel lug to allow the mounting of a small, purpose-designed spike bayonet. This had been a required part of the Army's initial design requirement, but it was omitted in most production guns after Ha Dong-u argued that the barrel was neither long enough nor adequately strong for bayonet fighting.

Variants

The first Type 39 modification, which received no formal designation, was an interim solution applied in response to safety problems. During operational service in Maverica, Menghean soldiers found that the primitive safety was prone to accidents. With the bolt left forward, if the early Type 39 were dropped and fell butt-down, the momentum could be sufficient to make the bolt bounce back a few centimeters and return forward, chambering and firing a round in the process. Around the middle of 1940, the receiver design was slightly altered to include a notch above the charging handle's forwardmost point, allowing the operator to rotate the charging handle into a safe position with the bolt forward. Some existing Type 39s appear to have been modified, either at factories or in the field, to add such a notch. This was a modest improvement, but it became useless if the charging handle were knocked downward into the path of travel, a problem that also existed with the rear safety position.

A more comprehensive update came in late 1941. It was designated Type 39-ŭl, sometimes translated as Type 39-II. This featured a new hourglass-shaped charging handle and a straight opening for it to follow. On this configuration, the operator safes the bolt by rotating it 90 degrees and pushing it slightly inwards, a procedure which was deemed more reliable than locking the charging handle into its own catch. The rear tangent sight is also replaced by an L-shaped aperture sight which can be flipped to two positions. This sight actually has three range settings: the hole on the lower panel (100m), the hole on the upper panel (200m), and a V-shaped notch at the top of the upper panel (300m). The front sight is hooded to prevent it from getting caught on one's surroundings or being bent out of shape. A final change was the addition of a metal shield around the magazine release lever, to prevent it from being pressed accidentally; this is actually attached to the handguard rather than the magazine well.

The folding-stock variant, sometimes misidentified as "Type 39-III," is actually designated "Type 39 Compact Machine Pistol" (39식 소형 기관단총 / 三九式小型機關短銃, sam-gu-sik sohyŏng gigwandanchong). It has modified wooden furniture with a pistol grip and no solid buttstock, but is functionally identical to the original Type 39, and even comes in an "ŭl" version with improved sights and charging handle. It uses a skeleton-type buttstock similar in layout and stowage to that on the Ostlandian MP 40. The rear of the folding stock has an inverted "U" profile, with an open bottom, leaving space around the magazine well when folded under the handguard. It was issued mainly to airborne forces, though some wound up seeing action in urban combat on Menghean territory during the later years of the war.

The final Menghean variant of note is the "simplified" late-war version, or Type 39-byŏng. There was no single standard for these models, but in general they introduced further time-saving measures in order to create a weapon which small workshops could produce using the tools on hand. Most used a fixed rear sight with an aperture for 100 meters and a V-notch above for 200 meters, a reversion to the original bolt handle and safety, and a straight barrel without compensator notches, but some individual workshops made their own adjustments to suit the equipment they had on hand. In general the quality of manufacture on late-war weapons is very poor, and quality control was nonexistent.

Service

The Type 39 first saw service in early 1940 in the Themiclesian theatre. It was widely used in both Themiclesia and Maverica during the urban battles of 1940 and 1941, where it earned a good reputation among Menghean troops.

On paper, each Menghean infantry squad was to be issued a single Type 39 submachine gun, which would be operated not by the sergeant but by a regular enlisted soldier trained with the weapon. Production of submachine guns of all types was never sufficient to meet this demand in practice, and it's estimated that over the course of the war no more than half of all Menghean infantry squads were ever equipped this way. In contrast to the leading practice in some other countries, Menghean tank crews were never issued SMGs, relying entirely on pistols and carbines throughout the war.

Certain units, especially Marine Infantry and Airborne troops, received priority in Type 39 allocation, with two or even three SMGs per squad. In urban combat, some commanders also put together improvised "assault squads" with four SMGs and four rifle-armed SMG assistants, but this was only integrated into Menghean Army manuals in 1943 and it was never a permanent unit configuration.

Early-production Type 39s were actually built to a fairly high quality, and were well-regarded among troops in the field. With its moderately heavy receiver, lighter barrel and compensator, smaller projectile, and modest rate of fire, the Type 39 was relatively easy to keep on target during automatic fire. With few moving parts and controls, it was also easy for recruits to learn how to operate, maintain, and disassemble the weapon, and despite the use of a milled receiver production was fairly straightforward. The main complaints centered on safety, size, and the relatively open receiver design compared to contemporary Menghean weapons.

As the war dragged on, the quality of the weapon's manufacture steadily declined, especially for 1945 models made in rural workshops. To make matters worse, parts were still hand-fitted in the final stages of the assembly process, meaning that if Allied soldiers swapped out components among captured weapons they ended up with greatly reduced reliability. In particular, if the fit between the handguard and receiver end became too loose, the weapon could spontaneously unhinge during firing, a problem which was seldom recorded in Menghean Army service but often mentioned by Allied soldiers.

After the end of the Pan-Septentrion War, the Type 39 remained in use through the Menghean War of Liberation. Rural workshops continued to produce simplified Type 39s for guerilla fighters, as most parts were easy to turn out on a lathe, though these weapons had the worst safety and reliability problems of all. The Type 39 remained in use in the Democratic People's Republic of Menghe until at least the 1970s, mostly with police forces and rear-area guard units; some guns were rechambered and re-bored for the 7.62×25mm Tokarev round produced in the Federation of Socialist Republics and supplied via Polvokia, but others remained in 7.5×25mm Menghean, a cartridge no longer in widespread production.

See also

• Type 17 rifle
• Type 32 light machine gun
• Type 38 self-loading rifle