SMP-59 rifle

The SMP59 (Teutonic: Schweres Maschinenpistole 59, Anglic: Heavy Machine Pistol 59) is an Alvak produced by Lonopolis Kaiserliche Arsenal and first adopted in 1959.

The SMP59 was developed in Alva at the end of the Great Kesh War. When the Alvak Heereswaffenamt put a request out to the firearms industry for a replacement for its lacklustre MP45 machine pistol, the design that would become the SMP59 was submitted by the Lonopolis Imperial Arsenal. The rifle was originally intended to be a submachine gun and carbine replacement, chambering the new shortened 7.92x33mm cartridge (hence its "Heavy Machine Pistol" designation). However, following trials of the prototype rifles, it was found that the new assault rifle concept would be an exemplary replacement for its rapidly ageing RK40 semi-automatic rifles as well. The Alvak Reichswehr had found in its post-war studies that engagement distances during the war had averaged 300 meters and below, which was well within the effective range of new SMP59. Thus, when the SMP59 was adopted in 1959, it began service as Alva's primary service rifle which it would serve as until 2000 when it was replaced by the bullpup Sturmgewehr 1. Following a general designation reorganization in 1978, the SMP category was scrapped in favour of the StG (Sturmgewehr) designation, but the rifle would keep its name until its retirement.

It operates via a short-stroke gas piston with a tilting breechblock and chambers 7.92x33mm, feeding from 20- or 30-round detachable magazines. The round was developed by Alva in the 1950s by shortening its standard 7.92x57mm rifle cartridge with the ultimate goal of reducing recoil impulse, thus making the rifle more controllable in full-automatic fire. Poor ballistics proved to be a major downside to the cartridge, but the situation at the time of the new cartridge's development pushed it into acceptance. However, the new cartridge came too late, with the first batch of rounds put out the day before Alva's surrender.

Description
The SMP58, SMP59, and StG59 were different designations for what was essentially the same rifle with minor updates in production. The lesser-used SMP58 designation is thought to have derived from the pre-production variant of the rifle. The StG59 designation comes from the reorganization of military designations in 1978, although this name is not in wide use. The variety in nomenclatures resulted from the complicated bureaucracy during Moderate rule in Alva. Developed from the 1954 LMK(AWk) "light machine carbine" prototype, the SMP59 combined the characteristics of a carbine, submachine gun, and automatic rifle. SMP is an abbreviation of Schweres Maschinenpistole.

The rifle was chambered for the 7.92×33mm Haberlin/Kurz cartridge. This shorter version of the Alvak standard (7.92×57mm) rifle round, in combination with the weapon's selective-fire design, provided a compromise between the controllable firepower of a submachine gun at close quarters with the accuracy and power of a Gewehr 08k bolt-action rifle at intermediate ranges. While the SMP-59 had less range and power than the more powerful infantry rifles of the day, Reichsheer studies had shown that few combat engagements occurred at more than 300 metres (330 yds) and the majority within 200 metres (220 yds). Full-power rifle cartridges were excessive for most uses for the average soldier. Only a trained specialist, such as a sniper, or soldiers equipped with machine guns, which fired multiple rounds at a known or suspected target, could make full use of the standard rifle round's range and power.

Background
During the retreat of the Bakanese Imperial Army after the failed 1953 Vo Offensives, increasing numbers of semi-automatic Khanh Model 15 pistols and Hong Model 90 rifles were used by the Bakanese to cover their retreat – mostly elite units and non-commissioned officers – while some Bakanese rifle companies were completely equipped with Truong Model 1 submachine guns.

After experiencing high volumes of automatic fire from these weapons, Alvak commanders re-thought their small arms requirements. The Alvak Reichsheer had been attempting to introduce semi-automatic weapons such as the Repetierkarabiner 40, but these proved troublesome in service and production was insufficient to meet requirements. Several attempts had been made to introduce lightweight machine guns or automatic rifles like the failed 1948 LMG(KmW) prototype, but recoil from the powerful 7.92×57mm Hecker round was too difficult to control in automatic fire. The RK40 was also difficult to reload, as the action would often clamp down on inattentive soldiers reloading it if the rifle was not switched to safe, making it a generally disliked rifle.

On the other end of the calibre spectrum, the MP45 (by early 1951, production had switched to the MP45k variant) had consistently performed poorly. A major weakness was its 32-round magazine. Unlike the double-column, dual-feed magazine inserts found on the Tiperyn MKb. 35 submachine gun, the MP45 used a double-column, single-feed insert. The single-feed insert resulted in increased friction against the remaining cartridges moving upwards towards the feed lips, resulting in feed failures; this problem was exacerbated by the presence of dirt, sand, or other debris. Another problem was that the magazine was also sometimes misused as a handhold. This could cause the weapon to malfunction when hand pressure on the magazine body caused the magazine lips to move out of the line of feed since the magazine well did not keep the magazine firmly locked. Alvak soldiers were trained to grasp either the handhold on the underside of the weapon or the magazine housing with the supporting hand to avoid feed malfunctions.

By early 1954, it was becoming clear that action needed to be taken. Although various experimental rounds had been developed to one degree or another by this point, the Heer instead decided to select yet a new design, the Haberlin 8×33mm Kurzpatrone ("short cartridge"). This used a spitzer bullet and basic cartridge design of the standard 7.92×57mm Hecker rifle cartridge, cutting down the cartridge from the original 7.92×57mm Hecker to 7.92×33mm Haberlin. It was understood that this was not ideal, but it would minimize logistical problems.

Beginning of development
Contracts for rifles firing the 7.92×33mm Haberlin round were issued to both Ursa Metallwerke (whose design group was headed by famed gun designer Adham el-Meer) and Albrecht Waffenfabrik, were asked to submit prototype weapons under the name Leichtes Maschinenkarabiner 54 ("light machine carbine") or LMK54. Both designs were similar, using a gas-operated action, with selective fire. Since both rifles shared the title of Leichtes Maschinenkarabiner 54 the letters (UMw) and (AWf) were added to differentiate the two. In this case (UMw) and (AWf) were the first initial of each guns manufacturer Ursa Metallwerke and Albrecht Waffenfabrik AG. The Ursawerke rifle along with the less successful Waffenfabrik rifle were predecessors of the later SMP58 and 59. The majority of the SMP59's features came from the Ursawerke model, with the separate pistol grip, hammer firing system, and closed bolt coming from the Waffenfabrik design.

However, development slowed and eventually stopped as Alva pulled out of the war on the 24th of November, 1954. With the need to develop new weapon technologies rapidly fading away and with funding draining rapidly due to Alva's war reparations, the project was shelved.

Final development and adoption
Development restarted in late 1956 with limited progress.

Design details
The SMP operates by means of a gas-operated action very similar to that of the UPRZ's AVT series of semi-automatic rifles. The gas system is driven by a short-stroke, spring-loaded piston housed above the barrel, and the locking mechanism is what is known as a tilting breechblock. To lock, it drops down into a solid shoulder of metal in the heavy receiver much like the bolts of the UPRZ AVT carbine and Legantine FCA 7mm M45 series of semi-automatic rifles. The gas system is fitted with a gas regulator behind the front sight base, allowing adjustment of the gas system in response to environmental conditions. The piston system can be bypassed completely, using the gas plug, to allow for the firing of rifle grenades and manual operation. The SMP's magazine capacity ranges from 20 to 30 rounds, with most magazines holding 30. In fixed stock versions of the SMP, the recoil spring is housed in the stock, while in folding-stock versions it is housed in the receiver cover, necessitating a slightly different receiver cover, recoil spring, and bolt carrier, and a modified lower receiver for the stock. For field stripping the SMP can be opened. During opening the rifle rotates around a two-piece pivot lock and pin assembly located between the trigger guard and magazine well to give access to the action and piston system. This opening method causes a suboptimal iron sightline as the rear sight element is mounted on the lower receiver and the front sight element of the sightline is mounted on the upper receiver/barrel and hence are fixed to two different movable subassemblies.

Variants
The SMP59 underwent various changes throughout its service, with many additions made.

Standard variants
First iteration. Uses wood as handguard and stock material instead of polymer. Phased out early for the A2, which uses polymer. Rare on the market. Replaces wood for polymer for handguard and stock material. Polymer furniture would be solely used for future variants. Replaces automatic fire selection for a 3-burst fire to reduce ammunition consumption.
 * SMP59A1
 * SMP59A2
 * SMP59A3

Short variants
The Short variants were developed for use in covert operations by the Abwehr and Reichsnachrichtendienst, and for paratrooper use in the Luftwaffe. Featured a folding stock, shorter handguard, and (n)cm barrel. The integral bipod under the handguard was removed. Featured a sliding stock, shorter handguard, and (n)cm barrel. The integral bipod under the handguard was removed.
 * SMP59KA1
 * SMP59KA2

Caliber conversion variants
Calibre conversion to 6.5x40mmTK. Developed in response to Alva's entry into the NSC. Failed reliability trials and subsequently scrapped. Calibre conversion to the Lienzek 7.62×45mm. Developed in response to Lienzek acquisition of production license in 19xx. Passed reliability trials; x000 rifles in total delivered to Lienzeberg. Calibre conversion to larger 7.92×57mm Hecker. Passed reliability trials, but did not find success commercially. Fewer than 500 of these rifles exist.
 * SMP59/6
 * SMP59/7
 * SMP59/8