Cutaway model of two cartridges for the WW2 designed Russian 57x480 Zis-2 anti tank gun.
The design of the Zis-2 started in 1940 when it was expected that the German army would soon use heavier armour on the eastern front, and it was expected that the 45mm gun in service at that moment was not sufficient for it’s task anymore. However, the problem with the Zis-2 gun was that -although it had a good armour penetration- the gun and it’s ammo were difficult and expensive to produce, mainly due to the very long barrel, which was 3,95 mtrs long. (L/69,3!). Therefore it was soon descided to switch production in favour of the cheaper and easier to produce 76,2mm Zis-3 gun.
In fact it was found that the 57mm Zis 2 was so powerful that it went straight though the relatively thin armoured German tanks from side to side, so in fact overkill. Therefore production was seized in 1941 after 371 guns had been produced.
Later in the war, the Panther and Tiger series of tanks appeared on the battlefield, against which the Zis-3 gun was helpless, exept when shooting from a short distance in the side or back. The Zis-2 however was able to penetrate these tanks in the side from greater distances, so it was taken into production again. By the end of the second world war 9.645 Zis-2 guns were produced.
The Gun was also tested in the T34, there called the Zis-4, and the tank was called the T34/57, but this wat not taken into service in large numbers, as the T34 was now being equiped with a new turret with the 85mm anti aircraft gun.
After WW2, the Zis -2 was placed in the ASU-57 assault gun for airborne troops. This gun could be parachuted from a transport plane. It was the combination of a light artillery tractor with thin aluminium armour and the 57mm Zis-2 gun.
The Zis-2 gun was used by: Albania, Bulgaria, China, Congo, Cuba, Czechoslovakia, East Germany, Egypt, Hungary, North Korea. Poland , Romania, Yugoslavia, Sowjet Union.
The gun still seems to be in active service with North-Korea, as a few years ago crates with 57mm Zis-2 ammo were found in a North-Korean merchant ship that was inspected due to the N-K arms embargo.
Left, the UBR 271P HVAP (High Velocity Armour Piercing) cartridge with an arrowhead projectile which has a weight of 1,555 kg and a Vo of 1270 mtr/sek.
The projectile consists of a mild steel shell body with an aluminium nose cap. A 0,51 kg Tungsten core with a length of 91 mm and a diameter of 24mm is placed inside the projectile body, glued in place with a white paste.
The brass shellcase is filled with 1,6 kg of granular powder. The colour of the projectile is grey or green.
Armour penetration is: 145mm @ 60 degrees at 100 mtrs.
190mm @ 90 degrees at 100 mtrs.
145mm @ 90 degrees at 500 mtrs.
83mm @ 60 degrees at 1000 mtrs.
101mm @ 90 degrees at 1000 mtrs.
Right, the UO-271U high explosive fragmentation cartridge. The projectile has a weight of 3,683 kg and is filled with 0,21 kg of TNT. Vo: 700 mtrs/sec. It is fuzed with the KTM-1 fuze, an impact and graze fuze.
The projectile body is made of mild steel and has two copper driving bands. Below the fuze a threaded flange is placed, locking up the explosive charge.
Description and functioning of the KTM-1 fuze:
The KTM -1 fuze consists of an upper (1) and lower (2) fuze body. The firing pin (3) and a ring with four ‘fingers’ (4) pointing inwards is placed in the upper part. The lower part houses the inertia weight (5) with the firing cap. A sheet metal locking ring (6) with four outward pointing strips is placed over the inertia weight. An inertia safety ring (7) is placed over the sheet metal ring, held in upper position by a presure spring(8 ), placed below it. The lower side of the inertia weight with the firing cap has a protruding cilindical part that fits the flash hole, ensuring that if the firing cap accidentally explodes, the flame cannot reach the detonator (9), preventing accidental explosion.
Upon firing the inertia safety ring (7) is swung backward, riding the spring (8 ) and bending the four strips (6) inward. These four strips lock in a groove on the inside of the inertia safety ring (7), fixating the inertia safety ring, the locking ring and the inertia weight with the firing cap together. When the acceleration is over , the spring pushes the assembly forward until it is stopped by the ring with the four inward pointing fingers. This means the firing cap has moved forward enough to allow the firing pin to move into the firing cap upon impact. Upon graze , the assembly with the firing cap will move forward due to descelleration, bending the four finger (4) upward, pushing the firing cap into the firing pin. This wil explode the detonator (9), which will ignite the booster charge (10), which ignites the main charge in the shell body.
Exept for these two shells, the following shells were available for the Zis-2 gun: the UShch-271 cannister shot, the UBR-271 armour piercing high explosive shell with ballistic cap, the UBR-271SP armour piercing shell with tracer and ballistic cap, and the UBR-271K armour piercing high explosive shell without ballistic cap.
Regards, DJH
The design of the Zis-2 started in 1940 when it was expected that the German army would soon use heavier armour on the eastern front, and it was expected that the 45mm gun in service at that moment was not sufficient for it’s task anymore. However, the problem with the Zis-2 gun was that -although it had a good armour penetration- the gun and it’s ammo were difficult and expensive to produce, mainly due to the very long barrel, which was 3,95 mtrs long. (L/69,3!). Therefore it was soon descided to switch production in favour of the cheaper and easier to produce 76,2mm Zis-3 gun.
In fact it was found that the 57mm Zis 2 was so powerful that it went straight though the relatively thin armoured German tanks from side to side, so in fact overkill. Therefore production was seized in 1941 after 371 guns had been produced.
Later in the war, the Panther and Tiger series of tanks appeared on the battlefield, against which the Zis-3 gun was helpless, exept when shooting from a short distance in the side or back. The Zis-2 however was able to penetrate these tanks in the side from greater distances, so it was taken into production again. By the end of the second world war 9.645 Zis-2 guns were produced.
The Gun was also tested in the T34, there called the Zis-4, and the tank was called the T34/57, but this wat not taken into service in large numbers, as the T34 was now being equiped with a new turret with the 85mm anti aircraft gun.
After WW2, the Zis -2 was placed in the ASU-57 assault gun for airborne troops. This gun could be parachuted from a transport plane. It was the combination of a light artillery tractor with thin aluminium armour and the 57mm Zis-2 gun.
The Zis-2 gun was used by: Albania, Bulgaria, China, Congo, Cuba, Czechoslovakia, East Germany, Egypt, Hungary, North Korea. Poland , Romania, Yugoslavia, Sowjet Union.
The gun still seems to be in active service with North-Korea, as a few years ago crates with 57mm Zis-2 ammo were found in a North-Korean merchant ship that was inspected due to the N-K arms embargo.
Left, the UBR 271P HVAP (High Velocity Armour Piercing) cartridge with an arrowhead projectile which has a weight of 1,555 kg and a Vo of 1270 mtr/sek.
The projectile consists of a mild steel shell body with an aluminium nose cap. A 0,51 kg Tungsten core with a length of 91 mm and a diameter of 24mm is placed inside the projectile body, glued in place with a white paste.
The brass shellcase is filled with 1,6 kg of granular powder. The colour of the projectile is grey or green.
Armour penetration is: 145mm @ 60 degrees at 100 mtrs.
190mm @ 90 degrees at 100 mtrs.
145mm @ 90 degrees at 500 mtrs.
83mm @ 60 degrees at 1000 mtrs.
101mm @ 90 degrees at 1000 mtrs.
Right, the UO-271U high explosive fragmentation cartridge. The projectile has a weight of 3,683 kg and is filled with 0,21 kg of TNT. Vo: 700 mtrs/sec. It is fuzed with the KTM-1 fuze, an impact and graze fuze.
The projectile body is made of mild steel and has two copper driving bands. Below the fuze a threaded flange is placed, locking up the explosive charge.
Description and functioning of the KTM-1 fuze:
The KTM -1 fuze consists of an upper (1) and lower (2) fuze body. The firing pin (3) and a ring with four ‘fingers’ (4) pointing inwards is placed in the upper part. The lower part houses the inertia weight (5) with the firing cap. A sheet metal locking ring (6) with four outward pointing strips is placed over the inertia weight. An inertia safety ring (7) is placed over the sheet metal ring, held in upper position by a presure spring(8 ), placed below it. The lower side of the inertia weight with the firing cap has a protruding cilindical part that fits the flash hole, ensuring that if the firing cap accidentally explodes, the flame cannot reach the detonator (9), preventing accidental explosion.
Upon firing the inertia safety ring (7) is swung backward, riding the spring (8 ) and bending the four strips (6) inward. These four strips lock in a groove on the inside of the inertia safety ring (7), fixating the inertia safety ring, the locking ring and the inertia weight with the firing cap together. When the acceleration is over , the spring pushes the assembly forward until it is stopped by the ring with the four inward pointing fingers. This means the firing cap has moved forward enough to allow the firing pin to move into the firing cap upon impact. Upon graze , the assembly with the firing cap will move forward due to descelleration, bending the four finger (4) upward, pushing the firing cap into the firing pin. This wil explode the detonator (9), which will ignite the booster charge (10), which ignites the main charge in the shell body.
Exept for these two shells, the following shells were available for the Zis-2 gun: the UShch-271 cannister shot, the UBR-271 armour piercing high explosive shell with ballistic cap, the UBR-271SP armour piercing shell with tracer and ballistic cap, and the UBR-271K armour piercing high explosive shell without ballistic cap.
Regards, DJH
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