Wider or Longer?

 

"Based on results of artillery trials of an IS-122 SPG in the amount of 438 shots (222 supercharged) the Gorohovets ANIOP makes the following conclusions:

• The 122 mm IS-122 self propelled gun passed proving grounds trials and can be accepted into mass production.
• The IS-122 has the following advantages over the IS-152 self propelled gun-howitzer, such as:
• Rate of fire is twice as high.
• Ammunition capacity is higher (30 rounds instead of 20 like in the IS-152).
• Muzzle velocity and penetration are higher (by 20%).
• The maximum range is longer (by 3 km).
• It is easier for the crew to work, load ammunition, and prepare for battle.
• Fire at moving targets is more effective."

Via Yuri Pasholok.

How to Kill a Tiger

There were many guides on how to take out Tiger tanks printed in the Red Army. I've shown two of them here, but this one is a lot more detailed.

Heavy Tank Destroyers that Remained on Paper

The KV-14 (SU-152) SPG was accepted into service on February 14th, 1943. It was designed primarily to combat enemy fortifications, but its first use in combat pitted it against German tanks. Work on tank destroyers on the SU-152 chassis began in the spring of 1943. Even though none of these projects was implemented in metal, the work eventually led to the ISU-122.

IS with a Heavy Gun

The tank that went into production under the name IS-85 was only a temporary solution. By the time GKO decree #4043 "On the production of IS tanks" was signed, the military already considered the 85 mm D-5T gun insufficiently powerful. Experience in fighting new German tanks at Kursk confirmed this. Because of this, the IS-85, also known as IS-1, was produced in limited quantities of just over 100 units. The role of the main heavy tank of the Red Army in the concluding period of the war fell to the IS-122, also known as the IS-2. Interestingly, work on this tank began long before Kursk.

Firing at Ferdinands

"Characteristics of armour penetration of cannons and effectiveness of mines on enemy tanks

Based on experience of combat and trials

1. Trials against an 88 mm SPG "Ferdinand" show the following results:
1. Armour of the SPG: roof: 45 mm, rear: 80 mm, side: 80 mm, front: 200 mm, gun mantlet: 110 mm, front hull: 200 mm.
2. Effectiveness of firing:
1. Anti-tank rifles: firing at the side armour from 80-100 meters with the BS-41 bullet penetrates 50 mm of armour forming a 20-22 mm deep indentation. Firing at the tracks can break track pins and the track links. The rifle can penetrate observation periscopes and jam the gun ball mount.

Tiger Manual

"

Translated from German.

Supreme Command of the Land Forces

4300/43 Secret

October 30th, 1943

Combat training instruction #14
Usage of PzKpfw VI Tiger tanks

Rules were composed based on summarized experience of units that used the PzKpfw VI Tiger tank in recent battles.

1. Vulnerability of the tank

The frequently displayed opinion about the invulnerability of the PzKpfw VI is a mistake, and often leads to improper use of the Tiger tank, which causes excessive losses.

4th Guards Infantry Corps Artillery Review

"AT Artillery

The 45 mm anti-tank guns mod. 1937 and 1942, despite all of their tactical, technical, and design qualities (good mobility, off-road performance, ease of concealment, and reliability in battle) cannot be used in the Red Army in the future due to the weakness of its shell against modern tanks.

It is reasonable to replace 45 mm guns with regimental batteries of 57 mm AT guns, which is a very powerful gun. Introduce an APC as a method of transportation for this gun that can provide protection for the crew during movement and repositioning.

The 76 mm ZiS-3 has good range and good point blank range, as well as a good rate of fire,  and performed well against tanks in the Great Patriotic war. Only against the German King Tiger tanks was the ZiS-3's shell insufficient. It is necessary to increase the muzzle velocity of the shell. The gun is light, maneuverable in battle, does not jam often, all mechanisms work precisely and flawlessly.

It is necessary to have an APC for AT units armed with 76 mm guns.

Infantry support artillery

The 45 mm gun mod. 1942 is very maneuverable, precise when shooting over open sights, and works well when firing at MG nests and portholes in pillboxes and dugouts. All gun mechanisms work flawlessly in battle.

Since the gun is almost always among infantry, it is necessary to make a double gun shield with sloped sides to protect the crew from bullets.

The 45 mm gun should be retained as an infantry support weapon only, as it did not fare well as an anti-tank gun and should be replaced with 57 mm guns.

During the Great Patriotic War, the 76 mm regimental gun mod. 1927 proved itself as an infantry support gun and in battle against light and medium tanks with HEAT shells. However, the mount does not allow firing at tanks easily and makes the gun clumsy. The muzzle velocity is low and the gun is relatively heavy. All mechanisms work flawlessly in battle.

The 76 mm regimental gun mod. 1943 is a good gun for infantry support only. It is light, mobile, its mechanisms work flawlessly. On the other hand, it is completely unsuitable for fighting tanks. Due to this, we reached the conclusion that it is much more reasonable to introduce a universal gun into infantry regiments (for both infantry support and anti-tank work), the 76 mm ZiS-3 gun.

It is necessary to introduce a six-horse carriage for this gun.

The 76 mm ZiS-3 gun is entirely satisfactory in its range, has a sufficient rate of fire in various battlefield conditions. Its shot has sufficient penetration against tanks (100 mm at 200 meters with a subcaliber shell). The gun is also entirely satisfactory to infantry, as its fire is effective against enemy troops. The gun is maneuverable and very well adapted to being towed mechanically. It is necessary to introduce an APC to tow this gun.

The authorized gun crew is entirely satisfactory for servicing this gun.

The existing shells and propellants are entirely satisfactory for completing tasks assigned to this gun.

The highest acceptable speed during march is 30-40 kph, depending on the transport. In battle, the ZiS-3 gun performed various marches, with the speed also depending on the transport. The longest marches were 250 km per day on paved roads. The existing sight is entirely satisfactory in modern battle and does not require any changes.

During movement and firing, the axle can be deformed (it is weak and bends). It is necessary to reinforce the axle or introduce a new one. Other mechanisms and components wear down with comparable speed. When towing the gun with horses, leave behind the propellant crate and limber, as it is extra unnecessary weight during towing.

The gun needs to have parts and instruments kits at the gun, battery, and regiment level consisting of: a spare assembled striker mechanism, artillery technician's bags, necessary wrenches, a double pump, and a return gear test device. Each gun needs to have a jar for storing lubricant and a testing rod. Store the gun kit with the gun and the battery and regimental kits in the regimental warehouse.

The 122 mm mod. 1938 howitzer showed itself well as an infantry support measure when destroying medium fortifications (wire obstacles, trenches, pillboxes with light coverage, dugouts).

The range and rate of fire are entirely satisfactory for completion of tasks assigned to this gun in various battle conditions and types of fire. However, the 122 mm howitzer cannot be used specifically as an anti-tank gun, as it is heavy, not mobile, and has low muzzle velocity.

The 122 mm howitzer has low dispersion due to its weight. It satisfies all requirements and demands given by infantry. As a divisional system, it is sufficiently maneuverable. A wheeled artillery tractor is most appropriate for towing this gun (three axle, like a Studebaker).

The authorized gun crew is entirely satisfactory for servicing this gun. The existing shells and propellants are also entirely satisfactory for completing tasks assigned to this gun.

The gun's springs let is be towed at a speed of 60 kph on good roads and up to 15-20 kph on bad roads. An average daily range depends on the type of transport. Situations occurred when the gun travelled 250 km.

The sights are sufficiently stable and perfected. It is desirable to replace the independent angle sight with a side level on the normalized sight, as, due to its complexity, it is prone to error.

Aside from existing ammunition for the 122 mm howitzer, it is desirable to add canister shot and increase the amount of HE-smoke shells, as the demand for the latter exceeds supply.

The gun is convenient to convert from travel to firing position, and it takes 1-2 minutes to do so.

The gun has no characteristically unreliable parts during travel and firing, all mecanisms wear evenly. When maintained well, the iron case can be used as much as the brass one. It is possible to use either one twice without sending it to the factory, as expansion is negligible. For this, it is necessary to supply spare primers. Reloading these shells should be done at field reloading workshops.

The existing parts and instruments kits for the 122 mm howitzer (gun, battery, regiment) sould be left alone. Store the gun kit with the gun, battery and regimental kits with artillery workshops. Keep a spare striker mechanism, a jar of lubricant, wrenches for fuses, primer plugs, and extractors. Have one double pump per battery, with a hose, manometer, a device for measuring fluid in the return gear, special wrenches, an artillery technician's bag. Store the rest at the artillery workshop.

The 122 mm gun and 152 mm gun-howtizer showed themselves well in the Great Patriotic War. The range, rate of fire, and especially accuracy were always satisfactory for completing any task assigned to corps or army artillery. When firing over open sights, the rate of fire of these guns is insufficient. A high muzzle velocity, and therefore point blank range, allows the 122 mm gun to fire directly at tanks, but the rate of fire and insufficient mobility due to its large size make the gun vulnerable to enemy tanks and artillery.

In good conditions, both systems satisfy the mobility requirement for cooperation with infantry. The following artillery tractors showed themselves well when towing these systems: ZiS-5 Voroshilovets, American ND-7 and ND-14 tractors. However, a lack of cargo area on the American tractors makes them insufficiently convenient.

The authorized crew size is sufficient for servicing the gun in battle. The existing shells and propellants are entirely sufficient for completing tasks issued to corps and army artillery. No addition to ammunition needs to be made.

All mechanisms worked flawlessly during firing.

Existing sighting mechanisms are very stable. It is desirable to replace the independent angle sight with a side level on the normalized sight, as, due to its complexity, it is prone to error.

The off-road performance of both systems with good transport is good. The maximum speed on the move is 30 kph.

The average daily range with an ND-7 or ND-14 tractor is 80-85 km

Due to complexity of the system and insufficiently trained crews, there were cases of bending the combat to travel conversion mechanism.

Sagging of the wheels can occur during travel due to wear of a rubber ring and breakdowns of the limber buffer spring.

During firing, neither system has characteristic failures. Most often, the wheel plug wears out the fastest, rendering the gun unusable. The spring leaves also fold due to insufficient robustness of the spring pins.

The mount, limber, and conversion mechanism of both systems needs to be redesigned.

Each gun needs to have: a spare assembled striker mechanism, fuse wrenches, primer plugs, jars for lubricant. Each battery needs to have an artillery technician's bag and special wrenches. The rest of the repair and parts kit can be stored at the regimental artillery workshop.

For artillerymen, the following weapons are most convenient:

• Gun commander: PPS
• Gunner: pistol or revolver
• Other crewmen: mod. 1944 carbine
• Radio operators and scouts: PPS
• Riders: carbine"

Via kris_reid.

Experimental Heavy SPGs

"122 mm A-19 SPG on the chassis of a SU-152 SPG
Kirov factory and factory #172

1. History of the project: when the production of the SU-152 began, the Artillery Committee decided to produce a 122 mm SPG by installing an A-19 gun in the SU-152 mount. In order to do this, the regional engineer of factory #172 was allotted one oscillating part of an A-19 gun with a 122 mm barrel, in accordance with the request made by the Kirov factory.
2. Progress: currently the Kirov factory is installing the oscillating part of the gun into a SU-152 SPG and is working on an ammunition rack. A prototype should be ready by May 10th of this year.

203 mm self propelled howitzer on the KV-1S chassis

Kirov factory and factory #172

1. The plenum of the Artillery Committee decided on April 15th, 1942, to develop a technical project for a self propelled Br-2 gun on the KV-1S chassis. Based on experience in constructing SPGs in 1942 and 1943, it was discovered that it's possible to install the B-4 howitzer into a semi-enclosed SPG on the KV-1S chassis.
   Kirov factory and factory #172 made an agreement with the 16th Department of the Artillery Committee to develop this project. Both factories are working in parallel."

CAMD RF 38-11369-91

Artillery at Kursk

Remember the ZiS-3 battery at Teploye that beat up some Tigers? That was only a small part of the battle. The overall engagement was much more grand.

Diagram 22. 3rd Anti-Tank Artillery brigade vs. enemy tanks, July 8th, 1943

The diagram shows an assembly of "up to 300 tanks and SPGs" against the anti-tank line, with an attack at 8:30, 11:30 (up to 200 tanks), 12:30 (up to 150 tanks), and 13:20 (up to 100 tanks). A German unit identified as "32nd Tank" broke through the line, but was repulsed by 2nd battery. 23rd and 16th tank units were also repulsed in the western part of the line. The 12:30 attack made some kind of complex maneuver over the positions of the 7th battery and retreated.

But enough about diagrams, let's look at some photos!

"German Tiger tank, destroyed by artillery from the 2nd Destroyer Division near Teploye"

"Fedinand SPG, destroyed on July 5th near height 257.3 by 4th battery, 642nd Gun Artillery Regiment, 5th Artillery Division, Reserve of the Supreme Command"

"German Ferdinand SPG destroyed by our artillery near Teploye."

"Inside of the Ferdinand SPG."

"Result of a direct hit by a 152 mm shell."

"Ferdinand SPG knocked out by our artillery."

"Two direct hits from 122 mm shells to the turret. Fire from 3rd battery, 642nd Gun Artillery Regiment, 5th Artillery Division, Reserve of the Supreme Command."

"Medium tank knocked out by direct hits from 76 mm shells, 7th battery, 1007th Light Artillery Regiment, 12th Artillery Division, Reserve of the Supreme Command, on July 6th, 1943, near Malaya Zorka."

"Tanks knocked out at height 257.1 by fire from 6th battery, 642nd Gun Artillery Regiment and 4th battery, 540th Light Artillery Regiment"

"A German tank after two hits by 152 mm shells to the turret. Destroyed at height 248.5 (Ponyri) on July 8th, 1943 by indirect fire from the 1st battery, 86th Heavy Howitzer Artillery Brigade."

"A German tank, destroyed on July 9th, 1943 near Ponyri station by 9th battery, 753rd Gun Artillery Regiment, 5th Artillery Division, Reserve of the Supreme Command."

"Ferdinand SPG destroyed on July 5th, 1943 near Podlesnaya by 4th battery, 753rd Gun Artillery Regiment."

"German Ferdinand SPG knocked out on July 6th, 1943, near height 255.1 by 3rd battery, 642nd Gun Artillery Regiment, 5th Artillery Division, Reserve of the Supreme Command. A 107 mm shell destroyed the track near the drive wheel."

"Ferdinand SPG knocked out on July 5th, 1943 near height 243.1 by 7th battery, 206th Howitzer Artillery Regiment, 5th Artillery Division, Reserve of the Supreme Command. A 122 mm howitzer shell destroyed the tracks."

"German medium tank and Ferdinand SPG (right) knocked out at height 257.1 (north) on July 8th, 1943 by direct fire from 6th battery, Corps Gun Artillery Regiment and 4th battery, 540th Light Artillery Regiment, 5th Artillery Division, Reserve of the Supreme Command."

"German tractor knocked out and burned up by fire from 2nd battery, 496th Howitzer Artillery Regiment, 12th Artillery Division, Reserve of the Supreme Command. July 15th, 1943."

"SPG hit by several 152 mm shells in the vicinity of 1st of May Farm"

You can see the rest of the photos from the album here.

Anti-Tank Defense Manual

"Directions to the Forces of the 2nd Ukrainian Front on Organization of Anti-Tank Defenses
#00408/2/op

May 30th, 1944

When organizing anti-tank artillery and engineering defenses, follow these instructions:

1. Heavy and divisional artillery must be arranged in a way that allows for long-range concentrated fire to disperse enemy tank formations and deal damage to them even at starting locations. Special long-range observation needs to be set up, and artillery must be ready to fire immediately when observers or aircraft call them.
2. Enemy tanks must be under artillery fire as soon as the attack begins and until they reach our lines. All tank-accessible directions must be split between batteries and squadrons. Maneuverability of fire must be such that when the main tank force appears in any direction, it can be fired upon by other artillery units. This fire, in combination with machinegun and mortar fire, will disperse enemy formations and suppress their infantry.
3. At night, when it is impossible to observe the results of your fire, it is necessary to set up an immobile artillery barrage in tank-accessible directions 300-400 meters from our lines, reinforcing it with direct fire from the front lines. The latter aim with the aid of illumination flares, fired by infantry from front line trenches.
4. Keep in mind that no amount of indirect fire can destroy enemy tanks completely. The main foundation of the anti-tank defense must be direct fire anti-tank guns on the first line and in depth through the defensive line in combination with engineering obstacles, natural hazards, maneuvers from mechanized artillery, SPGs, tanks, and sappers with anti-tank mines. The use of the aforementioned methods must be accompanied by infantry tank destroyer squads with AT rifles, grenades, and KS incendiary fluid.
5. Set up mines in solid lines in front of the front line of defense and in between trenches. The first minefield should not be more than 30-50 meters away from the first trenches. The second minefield should be in front of the second or third line of trenches.
   On secondary directions, put mines only in front of the first line of trenches, around gun placements.
   In order to confuse the enemy, put mines on various sections of terrain 200-300 meters away from the front line.
6. All minefields and engineering obstructions on the front line must be guarded by AT guns. Assign each gun a section of the minefield that the gun's crew is responsible for protecting.
   Minefields in the most important directions must be protected by overlapping fire.
   Aside from direct fire AT guns, indirect fire guns of all calibers must also protect them. Make sure that the sectors of responsibility overlap. Pre-aim indirect fire guns and mortars on areas immediately ahead of minefields and on flanks.
7. Concentration of AT guns on especially important directions should be up to 25 guns per kilometer of front. Separate AT guns into three echelons. The first echelon is placed in the second line of trenches, the second and third echelons within 600 meters of each other. Secondary directions only have two echelons.
   The core of AT defenses of each echelon must be 76 mm divisional guns due to their superior penetration. Surround them with 76 mm regimental guns, 45 mm guns, and AT rifles. Do not allow for all artillery to fire and reveal itself when individual tanks or small groups are sighted. Individual guns and platoons assigned to this role should fight these tanks.
   There should be "lure" guns set up in the path of potential tank attacks. Their assignment is to fire from 1.5-2 kilometers and lure the tanks into attacking them, making them vulnerable to the rest of the guns, positioned in ambushes at the flanks. After "lure" guns do their duty, they must immediately retreat to prepared positions.
   All AT guns, especially those in the first echelon, should be dug in and camouflaged. Each gun should have at least two positions 25-30 meters apart with trenches allowing the gun to quickly swap between them.
   The second and third echelons should have, if possible, 2-3 large caliber guns (85 mm AA guns, captured German 88 mm guns, 122 mm mod. 1931 guns, 122 mm howitzers, or even 152 mm gun-howitzers).
   Individual tank-accessible directions must have "dagger" guns and batteries, tasked with destroying particularly valuable targets and heavy tanks.
8. In order to increase the resistance of the AT guns, place guns or platoons behind natural obstacles, unless shooting conditions are worsened.
   If it is necessary to position guns in the open, cover the flanks of the AT guns with minefields.
   In order to more easily cover the flanks of the guns, stagger them.
9. If there is a shortage of AT mines, mine the most important sections first. Hidden paths towards the first line of defense take priority, as this forces the enemy tanks to approach in the open.
10. Protect artillery positions in depth from the front and the flanks with engineering obstructions, forming an anti-tank sector. Use existing natural obstacles.
    Protect minefields around artillery positions with machinegun and submachinegun fire. Additionally, have tank destroyer groups ready.
11. In places where tanks can only attack in certain places (ravines, dales, levees), lock down those directions with independent anti-tank regions with 360 degree defenses and minefields, combined with natural obstacles. Each region should have a squadron to a regiment of anti-tank artillery, 1-2 companies of infantry, and 4-5 SPGs. An anti-tank region is commanded by an artillery commandant. The garrison should be supplied with an emergency store of ammunition, fuel, and supplies. The personnel in an anti-tank region do not retreat, they either deflect the tank attack or die. The region is supported with indirect fire. In order to call down this fire, the commandant must have a diagram of pre-sighted points. The artillery is called by radio or with flares (same for aircraft).
12. Unlike independent anti-tank regions in part 11, main artillery positions in part 10 are placed deep inside the defenses. They must be placed in such a way that they can fire at least 600-800 meters forward and have overlapping fields of fire with neighbouring batteries. The overall system of batteries must also provide for 360 degree defense. Aside from tanks, the personnel of these positions must be prepared to fight enemy infantry that broke through.
13. As a rule, massed enemy tank attacks are accompanied by bombers and ground attack aircraft. Starting with first echelons and throughout the entire defensive depth, the AT gun batteries must be covered by AA measures (DShK machineguns, 37 mm and 85 mm guns).
14. The organization of AT defenses is organized by the artillery commander, approved by the combined arms commander. Anti-tank obstructions must be constructed in strict accordance with the AT defenses.
    Based on the artillery commander's decisions, compose a single map of AT and engineering defenses in the 25000 or 100000 scale with precise locations of all engineering obstructions as well as guns and batteries defending those obstructions and their fields of fire.
15. In order to increase the stability of the anti-tank defenses, reinforce important directions, and liquidate enemy tanks that break through, all division sized and greater units must have mobile anti-tank reserves composed of a squadron, regiment, or brigade of AT artillery, sappers with mines, SPGs, and tanks.
    Mobile reserves are composed of:
1. In armies, from AT gun units and Supreme Command Reserves.
2. In divisons, from AT gun squadrons and AT reinforcements.
16. The chief of the reserves must have a direct line of communication to the combined arms commander in his sector. Move reserves into battle on the orders of the combined arms commander.
17. In order to more effectively use reserves, artillery commanders must mark deployment lines in advance, approved by the combined arms commander. These lines must coincide with natural obstacles. Mine approaches to these lines for the AT artillery to cover. Carefully inspect them to determine the approaches tanks can take and the necessary number of mines. Commanders of these units must personally examine these regions and organize the minefields.
18. Use the engineering reserves depending on the use of artillery reserves. The engineers that act alongside the artillery must be subordinate to the artillery commander.
19. Engineering and artillery reserves must have necessary transport and be located in a location that ensures they can reach their deployment line and mine it before the enemy that broke through gets there.
20. During the preparatory period, the artillery reserve and engineering reserve commanders must organize training exercises on their positions in order to ensure minimal time is spent on deployment and mining.
21. There are two ways to use SPGs and tanks as a mobile reserve.
1. SPGs and tanks move out along with mechanized artillery and reinforce it on prepared positions.
2. SPGs and tanks set up ambushes along directions of enemy movement with the objective of flanking directions that lead to positions of the mobile reserves. In this case, aim to create a ring of fire so that tanks that are stopped by frontal artillery fire are destroyed from the flanks by tanks and SPGs."

Collection of Combat Documents from the Great Patriotic War, vol. 4, doc. 25

Counter-Counter-Attack Manual

"Orders to commanders of the 4th Ukrainian Front on fighting enemy tanks and SPGs in depth

When our forces penetrate enemy defenses and especially when they fight in depth, the enemy counterattacks with groups of tanks and SPGs. These groups act carefully from ambushes or fire on our attacking forces from two or more kilometers away. In areas where our infantry is not prepared to fight mobile enemy units, the offensive slows down or stalls.

The sensitivity of our first echelon troops to enemy tanks and SPGs can be explained by insufficiently effective organization of countermeasures to enemy tanks and SPGs. Current faults with our anti-tank defenses are as follows:

1. Infantry support artillery lags behind our lines, as a result of which when enemy tanks are encountered these guns are either silent or fire ineffectively from long distances.
2. Our tanks and SPGs also occasionally lag behind and maneuver poorly. There is insufficient cooperation between SPGs. As such, our tanks face significant losses when an ambush is encountered.
3. Observation of the battlefield is inadequate. There are no special observers looking for enemy tanks. Artillerymen often spot enemy tanks and SPGs either too late or not at all. There is no special signal for when tanks and SPGs are spotted.
4. Infantry and artillery does not use effective means to indicate the direction of tank attacks, so our artillery opens fire with a delay, fires in a disorganized fashion, often without observers.

In order to increase effectiveness when fighting enemy tanks and SPGs in depth and improve cooperation between infantry and tanks, commanders must do the following:

1. First echelon battalions (assault battalions) must be able to independently suppress and destroy enemy weapons, personnel, tanks, and SPGs. In order to achieve this, assign 3-4 tanks or SPGs, one 76 mm divisional gun battery, and 120 mm mortars. Guns and mortars need ropes to tow them behind advancing infantry by hand. An infantry squad must be assigned to each 76 mm gun to help their crews.
2. Each regiment in the first echelon of the advancing division must be assigned a 76 mm ZiS-3 gun battery with the sole objective of destroying enemy tanks and SPGs. These batteries must be maneuverable and daring. If tanks or SPGs appear out of effective range, the batteries must move forward under the cover of terrain or smoke. Attach men to these units from the rear and command platoons to help them push their guns. Equip the guns with ropes and entrenching tools.
   Each division must also have 1-2 122 mm guns or 152 mm gun-howitzers for the same purpose. These guns must follow infantry and destroy enemy tanks and SPGs at 1.5-2 kilometers. The divisional artillery commander must have a direct line of communication to these guns, either by radio or telephone.
3. SPG groups dedicated to battalion support must be composed of either mixed SU-76 and SU-122 SPGs, SU-152 SPGs, or SU-85 SPGs. Pay special attention to the cooperation between SPGs and AT gun batteries attached to the regiment or battalion.
4. As forces move out in areas where tanks are likely to appear, prepare suppressing and concentrated fire by one or two artillery squadrons or rocket artillery batteries, which open fire immediately as enemy tanks appear. When repelling tanks attacks, use carefully aimed indirect fire from heavy gun and howitzer batteries. 
5. In order to reduce the effectiveness of enemy tanks, especially heavy tanks, use smoke shells or bombs.
6. The main signal for signalling the approach of enemy tanks is smoke or mid-air detonations of shrapnel shells, as well as tracers from machineguns. Keep a supply of smoke or shrapnel rounds and tracers in forward batteries and machinegun squads.
7. Each observation point (artillery, infantry, tank, combined arms) must have special observers responsible for the detection of tanks that must report their appearance in the sector. Use aircraft, especially artillery spotters, to locate tanks in time.
8. Commanders of guns, batteries, squadrons, tanks, and SPGs, officers, sergeants and privates of other types of forces that excel at destroying enemy tanks and clear the way for infantry must be rewarded for each destroyed tank or SPG: the crew of the weapon responsible with an Order of the Patriotic War, 2nd class, the officer with an Order of the Red Banner.
9. These directions must be studied by all officers of artillery, infantry, tank, and engineering units.

Spread the word of rewards for destroyed enemy tanks and SPGs to privates and sergeants."

Collection of Combat Documents from the Great Patriotic War, vol. 2, doc. 09.

SU-152 with A-19

We've seen the idea of mounting an A-19 gun on a SU-152 before, but the plan was never actually implemented. Here is another iteration, with a little more reasoning.

"To the member of the Military Council of Armoured and Mechanized Forces of the Red Army, Lieutenant-General of the Tank Forces, comrade Biryukov

I report my ideas on the topic of armament of the SU-152 (on the KV chassis). The existing SU-152 SPG has one drawback along with many of its positive qualities, specifically that the ML-20 152 mm gun is basically a howitzer. As a result, when shooting at long ranges, on the order of 2000 meters, the angle of elevation is high and the target is no longer within the field of view of the sight.

Along with the 152 mm ML-20 gun, NKV factories produce the 122 mm A-19 gun, whose oscillating part is identical to the ML-20's. The A-19's shell has a flat trajectory, and the penetration of the gun is greater than that of any other gun used by the Red Army.

I think that it is reasonable and necessary to arm half of produced SU-152s with 122 mm guns. This will allow the SPGs to freely combat any existing enemy armoured vehicles at long ranges.

No design changes are necessary. All that must be done is the 152 mm barrel should be exchanged for a 122 mm one and new 122 mm ammunition racks should be installed.

I ask you to support my request to the director of the Kirov factory to produce one prototype of a SU-152 with a 122 mm A-19 gun. This SPG must undergo gunnery trials and the results of the trials will decide whether or not the tanks will be re-armed. The Kirov factory already has A-19 guns.

Chief of the GBTU Tank Directorate, Engineer-Colonel Afonin
Deputy Chief of the 6th Department of the Tank Directorate, Engineer-Major Voroshilov"

CAMD RF 38-11355-1401

KV-9 Trials

"According to order #012 of the NKO and the order #48s of the People's Commissariat of Tank Production, the commission led by Major-General of the tank forces comrade Ponov tested the KV-9 tank armed with the 122 mm M-30 howitzer from February 2nd to February 11th, 1942.

1. Goal of trials.

A KV-9 tank produced by the Kirov factory on the chassis of the KV-1 tank (see attachment #1) was submitted for trials. The KV-9 is armed with a 122 mm U-11 (M-30) howitzer designed by the Ural heavy machine building factory. The 122 mm tank howitzer is based on the stock divisional M-30 howitzer (see attachment #2). The KV-9 turret differs from the KV-1 turret in the following ways:

1. Increased gun port
2. Altered position of optical devices

2. Trials of robustness and precision.

The factory proving grounds tested the robustness of the gun mount using 171 increased power testing shots. Before trials, the mount was disassembled and measured. The recoil was within the limits of 560-580 mm. During firing, samples of gas concentration in the driver's compartment and fighting compartment were gathered. 

Additionally, the tank made 39 shots at targets at ranges of 600 and 1000 meters with shifts of fire at the Kopeisk proving grounds. The results of the shots are shown in the following table."

The following table does not list where the shots hit, but their time, range, and target are recorded. The tank can reload and fire in as little as 12 seconds, although the time is noticeably larger occasionally (when a target is reacquired, for instance). At 1000 meters, the tank shoots at a 5x5 meter target, at 600 meters, at a 1.25x1.25 meter target. 

"Note: during robustness trials, there were cases where the shell did not extract, which is explained by the use of old steel shells that have been re-loaded and the chamber being dirty.

All targets were hit directly. During gunnery trials, the tank drove 40 km over paved roads and 25 km off-road. The results of the trials are as follows:

1. The gun and mount system successfully passed robustness trials of 171 increased power shots. Measurements taken before and after trials have no difference between them, and are available in attachment 3.
2. The recoil mechanisms performed normally and passed trials (recoil remained within 560-580 mm). The pressure in the recoil brake was 27 atmospheres before trials, and 26.5 after.
3. The rate of fire is two rounds per minute.
4. The precision is good. Fire can be shifted quickly and without delay.
5. The elevation and turning mechanisms are comfortable to use.
6. The loader's position is cramped and makes his job difficult, but ensures the rate of fire of two shells per minute.
7. The ammunition rack is designed satisfactorily, aside from the following points:
1. The metallic cover should be replaced with a tarp.
2. Cut out the metal wall in the section covered by the tarp.
3. Increase the amount of shells in the turret bustle to 6 shells.
4. Bead form the metal to increase robustness.
8. The angle of depression is 2 degrees. It is desirable to increase it to 4 degrees.
9. The oscillating gun mantlet is not equal in thickness to the front of the turret, and some parts remain uncovered.
10. The frame cover is cast. It is necessary to use a stamped frame cover.
11. It is only possible to refill the brake fluid when the tank is tilted by 10 degrees or the recoil brake is removed.
12. The recoil brake pressure can only be checked when the gun is retracted by 300 mm. It is necessary to move the pressure valve.
13. There is no foot trigger.
14. Move the elevation indicator to the gunner's control panel.
15. Put a pear-shaped cushion on the periscope.
16. At high elevation, the elevation mechanism carrier can hit the gunner's guard plate. Make a slot in the plate.
17. Move back the sight 40-50 mm for more comfortable use.
18. Move the fault indicator, as it is covered by the machinegun.
19. The manual extractor is inconvenient; it slips off the shell rim.
20. Tighten the mount for the driver's mirror. There were two cases where is was shifted during fire.
21. The march stopper is reliable and allows to bring the gun into firing condition within 5-6 seconds.
22. The angles of deviation are not measured due to a lack of stock shots. The gun was fired using T-34 sights.
23. Move the DT machinegun up so that the disk magazine does not rub on the gun.
24. In order to find out the concentrations of gas in the tank, probes were taken after 30-40 shots with the engine off and hatches closed. The results are:
1. Fighting compartment: 0.201 mg/L
2. Driver's compartment: 0.308 mg/L
   With the engine on, the concentration is acceptable.

Penetration trials

On February 10th, factory #200 performed penetration trials using the U-11 122 mm tank howitzer and A-19 armour piercing shells. 

Trials conditions:

1. Shell mass: 24.6 kg (not entirely identical to stock)
2. The shells were fired at a stock cast KV turret (110-115 mm).
3. The distance between the muzzle and armour was 100 meters. The first load was 2100 grams of 9/7 powder and 0.030 of igniter. Muzzle velocity: 525.4 m/s. The shell penetrated the turret wall completely and remained behind the armour (see photo #1).
4. Second shot. Propellant charge: 2200 grams of of 9/7 powder and 0.030 of igniter. Muzzle velocity: 540.2 m/s. The shell punched out a plug and ricocheted (photo #2).
5. Third shot. Propellant charge: 2300 grams of 9/7 powder and 0.030 of igniter. Muzzle velocity: 546.4 m/s. Same results as the second shot (photo #3).
6. Fourth shot. Propellant charge: 2400 grams of 9/7 powder and 0.030 of igniter. Muzzle velocity: 573 m/s. Same result as the first shot.

Due to a lack of measuring equipment, the pressure in the barrel was not measured. It is necessary to discover the optimal amount of propellant at the Nizhniy Tagil proving grounds.

Conclusions:

1. The KV-9 tank passed trials and can be adopted into service with the Red Army.
2. When producing the KV-9, all aforementioned drawbacks must be corrected, with special care taken regarding the armour and ammunition rack.
3. As the 122 mm M-30 tank howitzer version passed trials, the commission deems it necessary to accelerate the mass production of the KV-9 tank.

February 16th, 1942"

CAMD RF 38-11355-668