The appearance of the Sa vz. 58 (Samopal vzor 1958 - “Automatic machine of the 1958 sample”) was associated with the signing of the Warsaw Pact and subsequent events. Soon after the founding of the Warsaw Pact, the member states began to standardize weapons and military equipment. In order to increase the overall fighting efficiency and simplify a number of important tasks, it was proposed to use the same or at least similar samples. In particular, one of the first steps in this direction was the adoption by all armies of the ATS of the intermediate cartridge 7,62x39 mm. Most of the ATS countries decided to adopt the Soviet automatic machine design MT. Kalashnikov. Some states began to buy ready-made Soviet-made samples, others purchased a license and launched their own production.
Czechoslovakia, proceeding from the desire to support its design school and industry, made a different decision. In 1956, the transfer to new ammunition was decided to be carried out in two stages. The first implied alteration of the available self-loading carbines vz. 52 under the new intermediate cartridge of the Soviet sample. In the framework of the second stage of the transfer, it was planned to create a promising automaton, originally designed for the use of the cartridge 7,62х39 mm. This approach allowed the army to be transferred to a new ammunition, as well as to avoid the use of foreign samples, thereby supporting its weapon industry.
The creation of a new weapon was entrusted to the company Česká Zbrojovka (Uherski Brod). The development manager was the engineer Jiri Chermak. Initially, in the secret documents, the new project appeared under the name Koště ("Broom"). The task of the project was to create a new automatic weapon under the intermediate cartridge 7,62х39 mm with characteristics at the level of the Kalashnikov assault rifles of the Soviet development. It was planned to produce new weapons at Czechoslovak enterprises, which affected some of the project requirements.
The easiest way to achieve the required characteristics was to copy or borrow ideas from Soviet weapons. Nevertheless, the designers under the leadership of I. Chermak decided to develop their own project based on original ideas. The result of this approach was the emergence of weapons that have a certain external similarity with the Soviet AK / AKM. However, the internal units of the two types of weapons had a lot of differences, which make the Broom product a full-fledged original design.
Prospective automatic weapons should have used automatics based on a gas engine. At the same time, the Czechoslovak designers did not copy any decisions of M.T. Kalashnikov and used in their project completely new ideas. As a result, the Koště automatic machine received a very interesting design and an unusual composition of the internal units.
The machine received a milled receiver box of the original design. The outer contours of this unit had a rectangular shape, and inside a set of guides was provided, along which the parts had to move. In addition, there were fastenings for springs, firing mechanism, etc., inside. The box received a shortened lid, which was supposed to close only the back part of it. The front of the receiver, in turn, should have closed the upper part of the bolt group. For attaching the cover to the receiver, a front latch and a rear pin were provided. An interesting feature of the project was the use of pins without the possibility of complete extraction: when removing parts, the pins remained in their fastenings.
In front of the receiver, on a massive monolithic block, on top of it was located the base of the sight, which also served as a support for the gas piston. It had a transverse through-hole for fastening the top cover of the forearm. Under the base of the sight in the box was fixed trunk. Directly in front of the forearm, there was a gas discharge unit with a chamber, which was responsible for the movement of the piston. In the muzzle of the trunk was a node equipped with a front sight and attachments for the bayonet.
An automatic machine designed by I. Chermak was completed with a rifled barrel of 7,62 caliber mm 390 mm long (51 caliber). In the middle of the trunk there was a vent hole connected to the corresponding outdoor units. Initially, the barrel of the machine was not completed with any additional devices, but later several variants of flame arresters appeared, which are necessary for solving special tasks.
The main element of the gas engine of the new machine has become a piston with a short stroke. It was made in the form of a metal rod with several thickenings. An enlarged front part of the piston entered the chamber of the gas exhaust unit, and a narrow shank with an emphasis should be placed in the hole of the base of the sight. There was also a piston's own return spring. During firing, the piston under the influence of powder gases and springs had to make reciprocating motion, pushing the bolt group and returning to its original position. To provide the required thrust to the slide group, the piston could move only a few centimeters.
The bolt group of the Koště submachine gun had an interesting structure, and also differed noticeably from the aggregates of other weapons of this class. Its main element was a slide frame of a complex section: its upper part was triangular, the lower part was rectangular. The entire length of the bolt carrier had cavities of various configurations, for example, at the back there were four holes located by a rhombus. The upper part included the return spring of the bolt group, two medium ones lightened the part, and the lower one was intended for a moving drummer. In the lower rectangular part of the bolt group, there were devices for mounting the shutter and controlling the movement of its parts. On the right side of the frame there was a handle for cocking the weapon.
Actually the machine shutter consisted of two main parts: the body and the larvae. The latter was responsible for locking the barrel before firing. During the movement of the bolt group, the bolt parts had to engage with the frame guides and move as necessary. With the extreme front position of the bolt, the swinging larva went down and captured the combat stops of the receiver. When uncoupling after a shot, the larva had to climb up and release the bolt.
A through channel for the installation of a moving drummer was provided inside the bolt carrier. The latter was made in the form of a massive tubular part with a thickened back part and edges on a narrow part. During firing, such a drummer had to catch on a whisper's tooth or move forward under the action of its own combat spring, producing a shot. Rollback and cocking of the drummer were made when the bolt movement backward.
A curious feature of the Broom project was the use of the original receiver cover, designed to hold two springs at once: return and combat. At the rear of the triangular cover was a mount for two springs. Above, directly under the "arch" of the cover, there was a return spring of the bolt carrier. Under it, below the level of the side faces of the cover, there was a combat spring of the drummer. To maintain the correct position, both springs had their own guides. The top was worn on the wire device, and the bottom was equipped with a relatively thick metal rod. When installing the cover on the receiver box, both springs had to go into the corresponding holes of the bolt group and the drummer.
The trigger mechanism of the automaton was built according to a shock pattern. He had a minimum of parts, but could provide firing single shots and bursts. When pressing the trigger, the sear should have let go of the drummer. The principles of the interaction of the sear and the drummer depended on the mode of fire. Above the pistol grip, on the right side of the receiver, there was a small flag of the fuse-translator of fire. Being turned down, the box blocked USM. His turn forward or back allowed to fire in the desired mode.
Gate group in the analysis. From left to right, top to bottom: bolt carrier, bolt larva, drummer and bolt. Photo Novarata.net
New ammunition box magazines for 30 cartridges 7,62x39 mm were proposed for the supply of ammunition. To a certain extent, they resembled the shops of a Kalashnikov assault rifle, however, they had several differences. So, the new design of the feeder and some other innovations were used. In addition, over time, the production of aluminum casings was started, which led to a noticeable reduction in the weight of the structure.
The store should be placed in the lower receiving window of the receiver. At the rear of the window was a spring-loaded latch. Due to the use of a relatively long lever, we had to modify the design of the trigger guard. Its relatively wide front part was divided into two halves, the left one having a concave shape and did not prevent the use of the latch.
Accessories of the first version of the machine should have been made of wood. To the rear wall of the receiver was attached wooden butt of a characteristic curved shape with a butt pad. Inside the butt, a channel was provided for storing a case with accessories. Under the receiver was a wooden pistol grip. To protect the hands from the heated barrel and the gas engine, the machine has received the shank of the combined wooden-metal structure. Its lower part was made in the form of a wooden device, fixed under the trunks. The top one was made of inner metal casing and outer wooden “shell”. The inner casing was supposed to protect the wooden part from the direct influence of powder gases from the chamber.
The latest series of machines received fittings of a different type. While maintaining the shape and size of the parts were molded from plastic with filling in the form of wooden chips. Such butts and handles were cheaper, but not inferior to wooden ones according to their main characteristics.
Sights consisted of a fly on a stand above the muzzle of the barrel and an open mechanical sight mounted above the chamber. The sight had markings for firing at a distance of up to 800 m. It was proposed to adjust the sight by changing the angle of the main rail and, as a result, the height of the rear sight.
The machine gun was equipped with a bayonet-knife with a single-sided blade and a wooden handle. For mounting on the weapon, the handle of the bayonet had an L-shaped metal part with a longitudinal groove and a latch. The protrusion should have included the corresponding protrusions of the muzzle of the barrel. With the help of the latch with the button bayonet was fixed in the desired position. For carrying the bayonet were leather sheath with a loop for hanging on the belt.
The original design of the automatics was supposed to work according to new principles. By placing the store in the receiving shaft and cocking the bolt, the shooter could set the fuse-translator in the desired position and fire. When the slide group was moved backward, the return and combat springs were compressed, and the hammer was fixed in the rearmost position. Moving forward under the action of the return spring, the slide frame was supposed to seize the upper cartridge from the magazine and send it to the chamber. Then the swinging larva of a lock made lock.
When the trigger was pressed, the drummer was released, which, under the action of the mainspring, would go forward and hit the cartridge primer. When fired, the powder gases should have been vented through the upper vent hole in the engine chamber and put pressure on the piston. The latter at the same time moved back and hit the front of the bolt carrier. After receiving the impulse, she rolled back and produced a shutter release. When moving back, the liner was thrown away, and the drummer was on the stop. The gas piston returned to its original position under the action of its own spring.
The bayonet and its scabbard. Photo Ak-info.ru
The total length of the new weapon reached 845 mm with a barrel length 390 mm. Machine gun with wooden fittings without ammunition weighed 3,1 kg. The mass of weapons with the magazine increased by about 500. Used automation provided the technical rate of fire at the level of 800 shots per minute. The effective range of fire, despite the marking of the sight, remained within the 400-500 m.
An order to begin developing a new machine has been received in 1956 year. It took about two years to complete all the necessary work, from design to testing. In the 1958 year, according to the test results, the new weapon of the Koště project was approved by the military and was put into service. The machine has received the official designation Samopal vzor 58 or abbreviated Sa vz. 58.
Soon the Czechoslovak industry mastered the mass production of new machines, and the troops began to receive these weapons and learn how to use them. Over the next few decades, the Sa vz. 58 was the main small arms of the armed forces of Czechoslovakia.
Based on the basic design of Sa vz. 58 created several modifications that differed from each other in only a few details. The processing of automation and internal units was considered inappropriate. The basic version of the machine was considered Sa vz. 58, also known as Sa vz. 58P (Pěchotní - "Infantry"). He had a wooden butt without the possibility of folding. A version of Sa vz was also developed. 58V (Výsadkový - “Landing”), which received a metal folding butt. Such a butt consisted of a U-shaped attachment on the receiver, a metal strap and a shoulder rest. To reduce the size of the weapon, the butt turned to the right and fit along the receiver.
Based on the "infantry" machine based modification, designed for use with a night sight NSP-2. This machine was equipped with appropriate mounts. In addition, in order to avoid “blinding” the sight with a flash of a shot, a flame arrester of new design was mounted on the barrel. This version of the weapon was called Sa vz. 58Pi.
Bringing its development to mass production, Czechoslovak designers began to develop its design. Already in the mid-sixties, I. Chermak and his colleagues began work on the use of new cartridges. The result was the emergence of two interesting prototypes. In 1966, the AP-Z 67 automatic rifle (Automatická puška) was introduced for 7,62x51 mm NATO. Four years later, the project ÚP-Z 70 (Útočná puška - "Assault rifle"), which involved the use of an intermediate cartridge 5,56х45 mm NATO. These projects were not brought to mass production.
After experimenting with ammunition, the Česká Zbrojovka team proceeded with other weapons processing. The result of this in 1976 was the emergence of an experimental machine (Experimentalnbra zbraň) EZ-B, built on the layout of bullpup. At the same time Ruční kulomet (light machine gun) KLEČ was created with the barrel extended to 590 mm. In the future, there were unsuccessful attempts to create on the basis of the machine Sa vz. 58 sniper rifle and submachine gun chambered for 9x19 mm Parabellum.
The enumeration of modifications of the base machine can be completed by mentioning the development of a sufficiently large number of civilian versions of weapons that differed from the prototype by various design features. In particular, the possibility of automatic fire was removed, the dimensions of all weapons and the length of the barrel were changed, and other changes were made.
Automatic with a closed bayonet and magazine pouch for stores. Photo Armoury-online.ru
Start customer Sa vz. 58 became the army of Czechoslovakia. Mass production of these weapons allowed for several years to abandon the use of outdated systems. Armed Czechoslovakia such machines consisted until the collapse of the country. In the future, the independent Czech Republic and Slovakia continued to operate the existing machine guns, although they attempted to put new weapons into service. Despite all the efforts that have been made, Sa vz. 58 has been used for several decades. In accordance with modern trends, relatively old automatic machines were equipped with Picatinny slats, new sights and other additional equipment, which to a certain extent enhanced their characteristics. Only at the beginning of this decade, the Czech Republic was able to complete a full rearmament and master the CZ-805 submachine guns. Slovakia continues to use old weapons.
Having completed the rearmament of its army, the Czechoslovak industry began exporting arms. Sa vz automatons. 58 were supplied to a significant number of foreign countries. third world. According to reports, deliveries were made in about two dozen countries. In addition, in one way or another, weapons fell on other armed formations. For example, along with the armies of Czechoslovakia, Angola, India, Vietnam, etc. Sa vz. 58 was used by Ulster loyalists (Northern Ireland).
Production of Sa vz. 58 lasted until 1984. For a quarter of a century, Czechoslovak enterprises managed to produce about 920 thousand automatic machines of several modifications. A characteristic feature of this weapon, according to shooters, was the high quality of performance and the corresponding reliability. Probably, this opinion is true, which indirectly confirms the duration of the use of weapons: the latest series of machines have more than thirty years and they, along with the older "brothers", are still used.
In the mid-fifties, Czechoslovakia decided not to purchase foreign weapons and not to collect them under license. On the contrary, it was decided to develop our own automatic machine, which allowed us to preserve our design school, as well as to provide industry with jobs. Both of these tasks have been successfully solved. In addition, the machine fully complied with the requirements and was able to reach mass production, providing the country with military weapons for half a century. This allows you to read the Sa vz machine. 58 is a successful model of small arms and a good competitor of the Soviet Kalashnikovs, as an alternative to which it was created. Nevertheless, the competition turned out to be very conditional, as clearly indicated by the number of weapons produced.
On the materials of the sites:
Detailed photo-review of the disassembling machine: