T-34 Rate of Fire Trials

 "March 1st, 1941
Approved by Proving Grounds Chief Colonel Romanov

Report on the experimental driver's observation device, ammunition racks, and commander's and loader's seats of the T-34 tank

...

Program of T-34 ammunition rack and rate of fire trials

1. Purpose of trial

1. To determine the practical rate of fire in various conditions of operation.
2. To determine the convenience of using the new ammunition rack.
3. To test the convenience of loading with the loader's seat folded

The New T-34

"Decree #428ss of the State Committee of Defense of the Council of Commissars of the USSR

November 19th, 1940

Moscow, Kremlin

On changes and additions to the tactical-technical requirements of KV, T-34, and T-40 tanks

...

On the T-34 tank, in addition to tactical-technical requirements approved by Committee of Defense decrees #45ss on February 27th, 1939, and #443ss on December 19th, 1939, introduce the following changes and additions:

1. The total mass of the T-34 tank is limited to 26 tons.
2. The approved armament of the T-34 tank is the 76 mm L-11 gun with the coaxial DT machinegun in the tank's turret, a second DT for the radio operator, and one submachinegun (PPD) in the turret to fire from hatches. Begin arming the T-34 tank with the F-34 gun starting with January 1st, 1941.

L-11 Installation

"To: AU, ABTU, 520, AU Military Representative at factory #183

The installation of the L-11 system in the A-34 tank can be done without changes to the following parts only:

• Gun barrel
• Recoil mechanism

As for the remaining parts, all of them must be changed to some degree, largely covered by the following:

1. Group 02: breech
1. The semiautomatic cutoff mechanism is removed and the roller cutoff mechanism from the L-10 is installed.
2. The breech handle is shortened by 20 mm.
2. Group 03: trigger mechanism
1. The hand trigger is different, and the attachment point is different.
2. The hand trigger (pedal) is used from the 45 mm gun.
3. Group 05: gun shield
1. The gun shield is completely different, including a coaxial machinegun. The telescope mount from the old gun shield is used, but with changes. The elevation mechanism sector is different.
4. Brass catcher: a new one with smaller dimensions (on the left side) will be used, with a trimmed stopper and a new carrier.
5. Frame: the L-11 frame is removed completely. The gun is mounted on two vertical posts welded from the inside to the front of the turret, replacing the frame.
6. Mantlet: a new one based on the changes to the gun shield and carrier.
7. Elevation mechanism is used from the L-11, but with small changes.
8. The periscope link is from the 45 mm gun.

Upgunning the A-34

"Act

We the undesigned, designer of plant 520 comrade A.A. Maloshtanov, representative of the Kirov factory comrade L.N. Kondrashev, representative of the AU comrade M.R. Vorzheinov, representative of plant 509 comrade E.S. Mezhevikin, compose the present act to certify that the following chances were introduced into the turret of the A-34 during the installation of the L-11 system:

1. The left carrier of the brass catcher is affixed to the mantlet, and because of this it is installed via an adapter.
2. The casing of the hand firing mechanism is installed in a new place, as a result of which the trigger was re-welded, the openings in the control panel were re-drilled, and the right side of the brass catcher was trimmed.
3. The recoil guard was trimmed as it clipped the recoil indicator.
4. The breech handle was shortened by 20 mm.
5. The shell catcher lock was shortened by 18 mm.
6. The elevation mechanism boss was trimmed.
7. A cylindrical handle was installed to rotate the PT-1 head instead of a flywheel.
8. Trigger pedals from the 45 mm system were used.
9. The semiautomatic mechanism cutoff from the L-10 system was installed (the cutoff from the L-11 doesn't fit).

All aforementioned changes do not decrease the quality of work of the L-11 system, except the L-10 cutoff, which does not allow firing with the semiautomatic mechanism disabled."

[signatures]

February 21st, 1940"

RGVA 31811-2-987 p.57

Substitute Standard

"To the Chief of the Main Department of Special Machinebuilding, comrade Surenyan

CC: Director of factory #183, comrade Maksarev

CC: Senior Military Representative at factory #183, Military Engineer 2nd Class Kozyrev

To complete the decree of the Committee of Defense of the Council of Commissars of the USSR #443/ss issued on December 19th, 1939, A-34 tanks will be produced with the L-11 gun and DT machinegun until the F-32 gun and DS machinegun are put into production.

At the same time, in order to begin production, I ask you to develop the mount for the F-32 gun and DS machinegun based on blueprints that were sent to the factory earlier. The tactical-technical characteristics of the F-32 gun mount are being sent to the factory.

Authorized representative of the Assistant of the Chief of the ABTU, Military Engineer 1st Class Korobkov

Autorized representative of the ABTU Military Commissar, Military Engineer 2nd Class Makarov

Authorized representative of the Chief of the 8th Department of the ABTU, Military Engineer 1st Class, Afonin

January 25th, 1940"

RGVA 31811-2-1181 p.12

F-32 in A-34

"Secret

To the ABTU Chief, Corps Commander Pavlov

NKO House, 2 Red Square, Moscow

On the issue of: production of armour and assembly of A-34 hull and turret.

The armour for the A-34 is ready, both for the hull and the turret. The hull is in the finishing stages of assembly, the turret assembly will begin on December 22nd.

Faster, Better, Longer

"April 13th, 1939
#227064

To: Director of the Kirov factory, comrade Zaltsmann
CC: Military Representative of the AU at the Kirov Factory, Military Engineer 2nd Grade Buglak

Work on producing an experimental prototype of a tank gun 30 calibers in length is, for some unknown reason, lagging behind all reasonable timeframes, despite being a relatively simple job.

Artillery Wishlist for 1940

The Supreme Military Council made a recommendation in May of 1940 regarding the state of artillery in the Red Army. The first half is about AA guns, and falls outside of the scope of this blog, but about halfway through, we get some juicy tidbits.

"
4. Consider large caliber artillery a task of utmost importance. Develop 210 mm field guns, 305 mm field howitzers in 1941, and 356 mm guns and 500 mm howitzers on rails for 1942. Develop and build prototypes of a 450 mm field howitzer in 1941.

5. On anti-tank guns:
Organize the manufacture of 45 mm shrapnel shells, producing 200,000 of them in 1940. GAU should develop an anti-tank gun, 50-60 mm in caliber, that can penetrate 50 mm of armour at 1000 meters.

Regimental guns:
Regimental guns currently being developed do not match the requirements of regimental guns due to being too heavy (900 kg). Currently developed guns should be completed and tested. In 1941, develop a new regimental gun, that weighs no more than 500 kg, has a 5 km range, and is not made for fighting tanks.
...
Medium caliber tank gun:
Leave the L-11 tank gun for 1940 Gradually shift to the F-32 and develop a new, more powerful tank gun  that is capable of fighting modern tanks. Hold the development of the F-32 until this issue is resolved.

6. On the armour piercing capabilities of field artillery.

Develop AP shells for the following artillery systems:

• 152 mm model 1938 howitzer
• 107 mm model 1910/30 gun
• 122 mm model 1931 gun
• 152 mm model 1935 gun
• 152 mm model 1937 gun"

As always, let's see how successful these requests were. The massive artillery isn't really my department (I included it for fans of large numbers), but it looks like they got somewhere, combining the 450 mm requirement and the rail requirement into...something.

CAMD RF 81-12104-36

The request for a 50-60 mm AT gun was met with the 57 mm ZiS-2. According to the table here, it overfulfilled the penetration requirement, with 75 mm of penetration (against armour at 30 degrees, no less) at 1000 meters. Similar results are achieved by the ZiS-4 here.

The request for a lighter regimental gun was almost satisfied with the model 1943 regimental gun. At 600 kg of combat weight, and with a 4200 meter range, it doesn't quite get there. Also, unlike in the requirement, it was issued with HEAT shells, making it capable at fighting enemy tanks at under 1000 meters.

The development of AP shells for the listed artillery systems was very much successful, and is explored in another article.

A GABTU wishlist for 1940 (CAMD RF 38-11355-10)  also has some artillery components in it:

"On artillery:

1. Immediately mass produce the 107 mm M-60 gun.
2. Order the 107 mm mountain gun.
3. Accelerate the trials of 203 mm howitzers.
4. Accelerate the trials of AP shells for 107 mm, 122 mm, and 152 mm guns.
5. Select the best possible 76 mm AP shell, and equip 76 mm model 1933 AA guns with it.
6. Develop armour piercing shells for the 122 mm model 1938 howitzer, 152 mm model 1937 gun-howitzer, and 152 mm model 1938 howitzer.
7. Develop armour piercing shells for 37 mm, 45 mm, and 85 mm AA guns."

GABTU's Tank Wishlist for 1940

The Red Army received a new heavy tank in 1940, and GABTU wasted no time before demanding more things from it. CAMD RF 38-11355-10 tells us the full story.

"

1. The KV tank must have a 76 mm gun with a muzzle velocity of at least 800 m/s, in order to penetrate 70-80 mm of armour at 1000 meters. The gun must fire quickly, and have sufficient stock of ammunition. Must have an armour piercing shell and a high explosive grenade.
   At this time, the most appropriate gun is the AA gun model 1931. The tank should also have 90-100 mm of armour.
2. The KV-2 tank must have a 107 mm gun with a muzzle velocity of 730-750 m/s in order to penetrate 100-110 mm of armour at 1000 meters. The gun must fire quickly, have high penetration, and have sufficient stock of ammunition. Must have an armour piercing shell and a high explosive grenade.
   At the time, the most appropriate gun is the 107 mm M-60 gun.
3. Build heavy self propelled armoured artillery to destroy pillboxes. Use a 122, 130, 152, and 180 mm guns. 
1. The most realistic way of solving this problem is the production of an SPG on the SMK or T-100 chassis, and installing a 100-130 mm gun on it, giving it an AP shell capable of penetrating 130-150 mm, and an HE shell. 
2. In short order, develop an experimental 152 mm model 1935 gun (Br-2) mount on the SMK tank, supply the system with an AP shell capable of penetrating 150-160 mm of armour, and a concrete wall 1.5 meters thick.
   The gun must be protected by 60-70 mm of armour and weigh no more than 65 tons.
3. Install a 180 mm gun on the SMK chassis. If necessary, alter the chassis, and reduce armour. [This entire paragraph is scratched out]
4. During the transitional period:
1. Manufacture KV tanks with a 152 mm model 1938 howitzer (M-10).
2. Manufacture KV tanks with L-11 guns and regular shells.
3. Immediately develop a mount for the 76 mm AA gun model 1931 and the M-60 107 mm gun.
4. Immediately begin producing the T-100 with a 130 mm gun, and begin work on installing a 152 mm model 1935 (Br-2) gun on the SMK.
5. Install 122, 130, and 152 mm guns on the T-35 and simultaneously test armour screens.
6. Have two types of T-34 tanks, ones with 45 mm guns, and ones with 76 mm guns. Improve the armour piercing capability of the 45 mm gun, and use F-32 or F-34 guns.
7. All tanks must use DS machineguns with thickened barrels, as they allow for longer continuous fire than the DT."

That's a lot of requirements. Let's go through and see which ones came true.

The first one came from the L-11's already insufficient AP performance. The F-32 gun that the KV-1 was stuck with had the same ballistic properties. The KV-1 didn't get a gun that satisfied this requirement until the ZiS-5. Next, the KV-2's 107. The tank was tested with a gun of that caliber, and it met the penetration requirements, but the KV-2 had no worthy opponents in 1941, and production ceased. 

Heavy self propelled guns are a whole different topic. The SU-100-Y definitely satisfied the 130 mm bunker buster requirement. The requirement for a mobile 152 mm gun wasn't met until the SU-152. The Br-2 was mounted on several self-propelled platforms, but never mass produced in that configuration. Its half-AP shell could penetrate 180 mm of armour, so that requirement is satisfied. 

The KV with an M-10 was certainly manufactured (KV-2). The KV-1 eventually switched to the F-32, and then ZiS-5 guns. The model 1931 AA gun was only ever tested in the T-34, and then discarded, as it was not necessary with the advent of the T-34-85. The T-100 with a 130 mm gun was the SU-100-Y, so that one was successful. The T-35 with a 152 mm gun wish was granted, in the shape of the SU-14, but only two were built.  

Plans were drafted to built T-34s with 45 mm guns in the event of a shortage of 76 mm guns, but such a shortage never happened. The T-34 received the F-34 in 1941. The AP capability of 45 mm guns was improved, with the 45 mm AT gun model 1942.

A number of these requirements was drafted with the Winter War in mind, when the Red Army was stuck on Finnish defensive lines. When Germany invaded, the USSR no longer had any use for bunker busters, as the bunkers they would have to one day storm were hundreds of kilometers away. Additionally, Germany did not bring any tanks with armour as thick as was foreseen, so 107 mm guns with ridiculous penetration were not needed.