Impact of a Zis-2 equipped Panzer III

[wiking85]

What if after encountering the Zis-2 and T-34/Kv-1 in 1941 the Germans opted not to go for the 50mm L60 gun for the Panzer III, rather the 57mm L73 gun the captured from the Soviets that they opt to make themselves? Its armor penetration was better than the F34 Soviet T-34 gun and could even penetrate the Tiger's armor. It should fit on the existing Pz III turret ring if that could handle the 75mm L24.
https://en.wikipedia.org/wiki/57_mm_anti-tank_gun_M1943_(ZiS-2)

 

[davebender]

They wanted a 75mm main gun which fired a far more effective HE shell then the Zis-2 cannon. 7.5cm KwK 40 cannon fit German requirements perfectly.

 

[Shortround6]

What if after encountering the Zis-2 and T-34/Kv-1 in 1941 the Germans opted not to go for the 50mm L60 gun for the Panzer III, rather the 57mm L73 gun the captured from the Soviets that they opt to make themselves? Its armor penetration was better than the F34 Soviet T-34 gun and could even penetrate the Tiger's armor. It should fit on the existing Pz III turret ring if that could handle the 75mm L24.
https://en.wikipedia.org/wiki/57_mm_anti-tank_gun_M1943_(ZiS-2)

Actually the Soviet 57mm has a lot more recoil than the German 75mm L24. Recoil being proportional to the weight of the shot times the muzzle velocity plus the weight of the propellant times the velocity of the escaping gas. A heavy gun does cut down on the recoil load but very high velocity guns use a lot of propellant. Muzzle brakes could be good for up to 30% reduction in recoil forces at that time
A British 6pdr was roughly 30% more powerful than the German 50mm/L60. The Russian Zis-2 gun fired similar weight projectiles to the 6pdr but at higher velocities. Like 20% better than the best of the 6pdr numbers for similar weight projectiles. To do that it burned about 30% more propellant. (about 1.45kg of propellant total). A 50mm/L60 used 882 grams of propellant behind the 'normal" AP shot.

 

[wiking85]

Actually the Soviet 57mm has a lot more recoil than the German 75mm L24. Recoil being proportional to the weight of the shot times the muzzle velocity plus the weight of the propellant times the velocity of the escaping gas. A heavy gun does cut down on the recoil load but very high velocity guns use a lot of propellant. Muzzle brakes could be good for up to 30% reduction in recoil forces at that time
A British 6pdr was roughly 30% more powerful than the German 50mm/L60. The Russian Zis-2 gun fired similar weight projectiles to the 6pdr but at higher velocities. Like 20% better than the best of the 6pdr numbers for similar weight projectiles. To do that it burned about 30% more propellant. (about 1.45kg of propellant total). A 50mm/L60 used 882 grams of propellant behind the 'normal" AP shot.

Good to know, thanks

 

[fastmongrel]

Would it fit into a PzIII its a big old lump of gun it looks much bigger than a British 6pdr 57mm/75mm QF and the US 75mm M3.

 

[Shortround6]

The Barrel is certainly longer.

Basically, if you could fit the Zis-2 you could fit the 76mm Zis-3, however the supply of replacement tank commanders might get a bit difficult.

Tank guns generally had much shorter recoil than towed guns even if they used the same ammo. Different hydraulic cylinders, buffers, recuperaters. A towed gun could have the breech block recoiling right through the tank commander if you just "stuck' it in the front of the turret. The shorter recoil distance increases the peak recoil load.
Granted the Germans could design and build a different recoil system but you are getting into a gun of such power that it is almost a 75mm/L43 in size and weight.