Czechpoint USA - History of the Sa vz. 61 - History of the Sa vz. 61 Scorpion

Development of the submachine gun in Czechoslovakia - post World War II

Experience from WWII showed that commanders in combat preferred submachine guns to pistols primarily due to the capability of shoulder fired full automatic fire. Semi automatic pistols were viewed by staff officers as defensive weapons only and the need was great for a submachine gun in both infantry and non-infantry roles. In 1949, a 9mm submachine gun began production and was adopted as the Sa 23 (fixed stock) and the Sa 25 (folding stock). Later, when Czechoslovakia joined the Warsaw Pact, the 9mm cartridge was changed to the Soviet 7.62x25mm and this resulted in the Sa 24 (fixed stock) and the Sa 26 (folding stock) model submachine guns.

The Sa 23 series was favored for its reliability, compact size, and full automatic fire capability. It is well known that the Sa 23 influenced Uziel Gal’s design of the Uzi submachine gun. However, the submachine gun was soon replaced by the Sa vz. 58 assault rifle in 7.62 x 39mm. After adoption of the vz. 58 rifle, the need arose again for a compact pistol caliber weapon capable of full automatic fire. This compact submachine gun was intended for use by reconnaissance units, Special Forces units, vehicle drivers, tank crews, army officers, and etc. In addition, the Ministry of Interior had expressed the need for a compact submachine gun and is believed to be the catalyst of the submachine gun project. The Ministry of Interior approached the Ministry of Defense with their request for assistance in the development of such a firearm. The Ministry of Defense combined the needs of the Ministry of Interior with the needs of the Army and created technical parameters and conditions for the new weapon. This new project was given the name of "Škorpion".

Designer of the Škorpion - Ing. Miroslav Rybář

The designer of the Sa vz. 61 Škorpion submachine gun is Ing. Miroslav Rybář. Mr. Rybář, who was born on March 12, 1924, successfully completed the Higher Industrial College of Engineering in Brno in 1943. After technical college he began work at Zbrojovka Brno. After liberation of Czechoslovakia, as the Czech universities opened up again, Mr. Rybář started his distance studies at the Engineering faculty of VUT (Vysoké učení technické) in Brno. In 1945, while continuing to work for Zbrojovka, he began work as a designer in tool making. Three years later, in 1948, Mr. Rybář fulfilled his long time dream and started to work in Zbrojovka´s Firearms Design Section.

In 1950 he graduated from university and achieved the title of Engineer (Ing.). After military service, in 1951, Rybář returned to small arms design, which was by then moved out of Zbrojovka Brno into the newly established company called Konstrukta Brno. It is here where he worked in the field of designing small caliber firearms and participated in working on a general purpose machine gun design – the model UK-59. In order to deepen his theoretical knowledge in the design of full automatic firearms, Rybář started post-graduate studies (1957) at the Military Technical Academy. At the end of his studies, in 1958, he successfully defends his design and final thesis – a small submachine gun called the Škorpion. After trial and evaluation, it was accepted by the Ministry of Defense for full scale production.

Even after finishing original design work on the Sa vz. 61 Škorpion, and seeing it through to serial production, Mr. Rybář continued to work on other modifications of the Škorpion – most notably the calibers of 9 mm Browning and 9 mm Makarov. In 1965 Rybář was promoted to Chief Engineer of the Arms Development Unit within the General Directorate of Zbrojovka Brno. However, after two years, he requested transfer back to his design office as he had missed the creative work found in small arms design. One year later, in 1968, he came up with yet another model of the Škorpion - the Sa vz. 68 in 9 mm Luger.

Ing. Miroslav Rybář, creative firearms designer and father of the Škorpion, passed away suddenly as the result of a massive heart attack. He died December 6, 1970, at the age of 46. When initial Škorpion production began, Mr. Rybář was 38 years old.

Technical Specifications of the Škorpion

Caliber

From today´s point of view, the 7.65 mm Browning (.32 acp) caliber used by the Škorpion is considered to be an insufficient submachine gun caliber. However, during the design of the Škorpion, the 7.65 mm Br. was the standard cartridge of many service pistols - including those in use by the Czechoslovak Ministry of Interior forces. Only in the late 1960´s, with the spread of international terrorism, did the 9 mm Luger begin to be adopted by interior security forces. Most agree that the 7.65 mm Br. is the most appropriate caliber for the design of the Skorpion – small size, light weight, but still capable of extreme accuracy and controllability during full automatic fire.

Design

The Škorpion was unique in its time. It uses the following common operational features found on a submachine gun: an unlocked bolt, magazine inserted into the bottom of the receiver (outside of the pistol grip) and a folding stock. These common features are combined with the following characteristics not usually found in submachine guns: extraordinary small size, fires from a closed bolt, and uses a rate reducer to slow full automatic fire.

The rate reducer mechanism contains the retarder lever (located at the rear of the receiver) that catches the cycling bolt momentarily. During this cycling, rearward travel of the bolt strikes the plunger weight causing it to be pushed downwards. This weight is located in the metal tube inside the pistol grip. The lever continues to hold the bolt to the rear until the moving weight is pushed up by the spring. Upon upwards travel, the weight trips the lever and the bolt is then released. This rate reducer slows the cyclic rate between 800 and 850 rounds per minute.

Š-59 Škorpion

In 1959, the first functional Škorpion samples were called the Š-59. These samples were almost identical to the final version of the Sa vz. 61. These slight differences included the following: folding stock permanently attached, shape of the pistol grip, and minor variances found in bolt, extractor, trigger guard, and magazine catch. This prototype, not requiring any major modifications to be implemented in final production, is a true testament to the genius of the original Škorpion design.

In 1961, Škorpion samples underwent rigorous testing and proved to be an extremely reliable firearm. It functioned flawlessly in severe temperatures ranging from –50 °C to + 70 °C. It proved just as reliable in wet and dusty conditions. Resistance against salt water was significantly increased when classic blackening was replaced by a high quality paint finish. The submachine gun also showed incredible resistance against mechanical damage: it withstood drops from heights of 10 m onto a clay surface and 6 m drops onto a concrete surface (this included drops directly onto the barrel). The Škorpion was also run over by an automobile without sustaining damage. In addition, the hard chrome barrel maintained accuracy up to 60,000 shots. Accuracy results included the following: at a distance of 50 m, without use of a folding stock, all rounds fired from 20 rd. magazine were placed into a diameter of 155 mm (6.10 in). At a distance of 100 m, with use of folding stock, the same 20 rds were placed into a diameter of 220 mm (8.66 in).

Production of the Sa vz. 61 Skorpion took place during the following years:

Trial pieces only:
1962 (total of 200)

Serial production:
1963 through 1966
1973 through 1976
1978 through 1979

Production resulted in a total of 210,000 Sa. vz. 61 Škorpions.

Technical specifications of the Sa vz. 61 Škorpion submachine gun

Caliber	7.65 mm Browning
Muzzle velocity	317 m/s
Maximum range	1,500 m
Lethal effect of the bullet	800 m
Effective range
- used as a pistol	75 m
- used with stock	200 m
Overall length with folded stock	270 mm
Overall length with extended	522 mm
Width of the weapon
- with folded stock	43 mm
- with stock unfolded	36 mm
Height of the weapon	167 mm
Barrel length	115 mm
Number of grooves	6
Sight radius	147
Weight of the weapon without magazine	1.28 kg
Weight of the weapon with full magazine
- 10 round	1.43 kg
- 20 round	1.53 kg
Technical rate of fire	820 rounds / min.
Practical rate of fire
- in semi-auto mode	35 rounds / min.
- in full-auto mode	350 rounds / min.

 

Proliferation of the Škorpion

The vz. 61 Škorpion has been adopted and/or used in the following countries:
Afghanistan, Angola, Croatia, Czech Republic, Egypt, Iraq, Ireland, Israel, Italy, Lebanon, Libya, Montenegro, Mozambique, Netherlands, Serbia, Slovakia, Uganda, Yugoslavia, and Zimbabwe.

Special note: Yugoslavia, after purchasing 30,000 vz. 61s, acquired the rights to a production license agreement to manufacture their own Škorpion – the Model 84.

Škorpion Models

Several other models were designed by Mr. Rybář and his team in the years following the introduction of the Sa vz. 61. These models differed mostly in caliber.

Sa vz. 64 was designed for caliber 9 mm Browning short. The differences in design between the Sa vz. 61 and the Sa vz. 64 included wider magazine well in the frame (due to the wider 9 mm cartridge), the addition of slanted cuts in the barrel (to act as a muzzle break to reduce recoil), and a straight magazine. As the energy of the 9 mm Browning Short cartridge is similar to that of the 7.65 mm Browning, no changes were required to the bolt and to the retarder/rate reducer mechanism.

Sa vz. 65 was developed for the 9 mm Makarov round (standard pistol and submachine gun caliber found in the Soviet Military). Externally, the Sa vz. 65 was identical to the Sa vz. 64 (except for the slant cuts found on the vz. 64 barrel). However, as the Makarov cartridge was more powerful than the 9 mm Br. cartridge, additional modifications were necessary to the vz. 65. One of the main modifications needed was to address the increased rate of fire. In the cavity in the rear side of the bolt, an insert with two tapered surfaces was added. The purpose of this modification was to push the retarder further down so the bolt (moving much faster due to the 9mm Makarov cartridge) could not jump off the hook of the retarder lever. Reliable functioning of the retarder meant that the same rate of fire could be achieved as the vz. 64. Also, a rubber bushing was placed at the bottom of the grip nut in order to lessen the impact of the retarder weight and extend the life of the retarder mechanism.

Sa vz. 68 was designed for the 9mm Luger cartridge. Mr. Rybář began work on the 9mm Luger Škorpion in 1967. This model was intended for export only as 9 mm Luger was considered, in those days, to be a “capitalist”caliber. 9mm Luger was not a small arms caliber found in any of the communist countries (with rare exception of some third world countries). The greater power of the 9mm Luger vz. 68 required modifications that had not be needed in the previous Škorpion submachine guns. Most notably, the bolt needed to be larger and heavier causing the vz. 68 bolt to be twice as heavy as the vz. 61. The vz. 61 had a bolt assembly weight of 230 g compared to that of the 460 g bolt of the vz. 68. In return, this caused an increased size of the frame and receiver. Similar to the vz. 65, the vz. 68 required the addition of an insert to reduce the impact of the retarder weight. Although, the insert used was a spring rather than the rubber bushing found in the vz. 65. Other modifications included: a new rear sight leaf increasing the distance to 250 m, the addition of loops for a sling, and the creation of a model with a fixed wooden stock.

Sa vz. 82 is the last modification of the original Sa vz. 61. This model used the “9 mm vz. 82” caliber - which is the Czech version of the 9 mm Makarov. It uses the same dimensions, but is loaded more powerful and uses a bullet made of sintered steel. As the request for this caliber came from Czechoslovak authorities sometime in the mid-seventies, a few years after Mr. Rybář´s death, Mr. Jiří Čermák (designer of the Sa vz. 58 assault rifle) led a team to develop this new model.

The biggest change to the original design concerned the frame, which until then was made by investment casting and finished by milling. The vz. 82 had a newly designed frame that was made from stamped sheet metal parts with shaped inserts welded together. Another significant change included a new polygonal barrel bore and replacement of the two cocking tabs to one larger one that could be placed on either side. This cocking tab/handle added to the overall width of the submachine gun, but made charging of the submachine gun easier with gloves in cold weather. A rubber bushing was used in the retarder mechanism, like that of the vz. 65, and the trigger mechanism was simplified. The trigger group was reduced from 9 parts to a total of 6. In addition, the folding stock was made telescopic.

Technical specifications of Sa vz. 61, Sa vz. 64, Sa vz. 65, Sa vz. 68, and Sa vz. 82

Model	vz.61	vz.64	vz.65	vz.68	vz.82
Caliber	7.65 mm Br.	9 mm Br.short	9 mm Makarov	9 mm Luger	9 mm vz.82 9mm Makarov
Barrel length	115 mm	115 mm	115 mm	130 mm	113 mm
Overall length	270/522 mm	270/522 mm	270/522 mm	305/595 mm	270/538 mm
Weight w/o magazine	1,280 g	1,280 g	1,323 g	2,003 g	1,440 g
Magazine capacity	10/20 rds	10/20 rds	10/20 rds	10/20/30 rds	12/24 rds

Summary

Of the five Škorpions developed, only the vz. 61 had entered serial production resulting in a total of 210,000 submachine guns produced. The remaining four models were never adopted by the army or the security forces.

The name and design of the Škorpion became both legendary and infamous. No other submachine gun has achieved its notoriety. This is founded through its unique design and proliferated use by communist governments, notorious regimes, and terrorist groups worldwide. Nevertheless, the Škorpion has become a legend among gun enthusiasts as well as the general public. Mr. Rybář died decades ago, but his masterpiece called the Sa vz. 61 Škorpion lives on.