Alternative light and anti-tank guns, 1935-45

[tomo pauk]

In the real world of the time the infantry wanted a truly man manhandle able AT gun and the 2Pounder was adequate and much more easily man handled than a larger weapon but conceived solely as a AT gun.

The 2pdr was pretty heavy for infantry to handle it, so it went to the artillery branch. Infantry was being outfitted with the French 25mm ATGs once in France.
The nominally larger AT guns were often lighter than the 2pdr, and by hundreds of kilos - like the Czech and Austrian/Italian 47 mm AT guns, as well as the Soviet 45mm M1932 ATG.

 

[bf109xxl]

The 57mms were pretty much the upper limit on moving by hand.

The 76mm ZIS-3 and even the 122mm M-30 could be moved by hand - there are plenty of photos. The problem with heavy anti-tank guns (e.g. PaK-40) was that the recoil spades buried during firing, and a tractor was necessary to pull them out.

 

[Shortround6]

The 2pdr was pretty heavy for infantry to handle it, so it went to the artillery branch. Infantry was being outfitted with the French 25mm ATGs once in France.

I am not sure about the reason. Not saying that the artillery didn't get the AT guns but the exact reason/s may be different. Might be more of a turf war than figuring out which branch of the service had better resources (trucks) for moving the guns. A bit like many of the 20mm AA guns the Germans had were in Luftwaffe units than traveled with the army because the Luftwaffe controlled everything that had to with the air.

The nominally larger AT guns were often lighter than the 2pdr, and by hundreds of kilos - like the Czech and Austrian/Italian 47 mm AT guns, as well as the Soviet 45mm M1932 ATG.

Very true. The actual gun and breech block were fairly light.
I would note that the Hungarians re-barreled a lot of Pak 36s with a 40mm barrel chambered for the 40mm Bofors round with only a small change in weight. Which kind of shows what the British could have done instead.

 

[Shortround6]

new infantry 2 Pounder and the smoke/HE job could be done with the existing mountain howitzer so would not finance the putative 6 Pounder so the design lay on the shelf

Not sure where this comes from.

British tank guns on the prewar years a complete mess, and they certainly did spend a lot of money for very little results.
The existing 3.7in Mountain howitzer was never used in a tank.
There was a 3.7in howtzer/mortar used in the A9/A10 and some A 13 cruiser tanks.
The shell was 10 1/2 lbs according to one source and the max range was around 2000yds, MV was about 620fps (189m/s) and chances of hitting a point target at ranges long than a Webley pistol could shoot were dim. It only weighed about 222lbs so it balanced in the 2pdr mount fairly well. HE shells were rare, one source claims only about 4 rounds out of the total but sometimes they didn't have even that.
This was replaced by the much more famous (or infamous) 3in howitzer which took over the Smoke/HE role. While the shell was just over 13lbs the velocity only increased a little bit and the range did not increase by more than 500 yds.
The 3.7in mountain gun barrel and Breech was about 451lbs. Won't fit in a 2pdr mount. And launching 20lb projectiles out the muzzle at the upper charge levels is going to break something fairly soo.

Nobody was making smoke shells in the 6pdr (57mm) caliber, You can't fit in enough chemical to make it worth while. You need to got to about 75mm to get smoke.

The mountain guns were NOT general issue infantry guns. They were used by special units. The 3in stokes mortars could fire smoke for the infantry for local support and the artillery (18pdrs and 25pdrs) where supposed to handle all the normal artillery support.

Now somebody is going to come up with the 2in mortar and smoke shells. They existed, they were used, but at short range for very specific targets and actually a lot of them were used for signaling, not creating sizable smoke screens.

Now the army and the bean counters should have been providing HE shells for the AT guns and tank guns from the start. A lot of men died because they didn't.
Anybody else that made artillery had figured out how to do it.

 

[tomo pauk]

The 76mm ZIS-3 and even the 122mm M-30 could be moved by hand - there are plenty of photos.

They were certainly being moved by human force. Trick is that it is easy to move a gun on a dry and even ground, while it is much harder to do it on and uneven ground where it rained a day or a week ago - and such a terrain is only to be expected in the NW & Central Europe.

 

[bf109xxl]

it is much harder to do it on and uneven ground where it rained a day or a week ago - and such a terrain is only to be expected in the NW & Central Europe.

Rolling ZiS-3s and M-30s by hand to support advancing infantry was a standard artillery technique throughout the war in any weather on any ground. The difference was that in some cases the crew could do it by itself, and in other cases infantrymen assistance was required.

 

[bf109xxl]

Russians had purchased/licensed the German 37mm gun and then designed a 45mm barrel for it and plunked the bigger barrel on the same carriage. It was not a Pak 38 but it penetrate at around 900 meters what the 37mm could do at 400 meters. Considering the "standard" German armor of 30mm (a bit heavier in the front) this was pretty good even if not outstanding.

...and because of this earned the ironic nickname of "Farewell to the Motherland!" among artillerymen (it means the inevitable tragic death of the crew).
The problem for the Soviets was the quality of the shells. And it was technologically easier to provide the required quality of an armor-piercing discarding sabot with a larger diameter (>=57 mm).

In addition. I apologize, I got it wrong though: technologically, 45mm shells were easier to produce, while it was more difficult to press a 76mm core made of tungsten carbide powder.
In general, the design of the projectile had no less influence on armor penetration than the gun ballistics. For example, the German PaK-35/36 demonstrated better penetration of armor with high hardness than the Soviet 45mm in 1941. The use of break off grooves ("localizers") dramatically improved the performance of Soviet 45mm armor-piercing projectiles without changing the ballistics of the gun itself.

The change in German tank armor during the war was so serious that it was hardly possible to offer anything more optimal in 1939-1941 than what was already available (for example, the Soviet 45mm was quite adequate except for the quality of the projectile manufacturing). And in 1942 the ballistics of the guns and the design of the projectiles would have to be changed anyway.

 

[tomo pauk]

...and because of this earned the ironic nickname of "Farewell to the Motherland!" among artillerymen (it means the inevitable tragic death of the crew).
The problem for the Soviets was the quality of the shells. And it was technologically easier to provide the required quality of an armor-piercing discarding sabot with a larger diameter (>=57 mm).

I'm not sure that Soviets were issuing the APDS shots back in ww2.

Rolling ZiS-3s and M-30s by hand to support advancing infantry was a standard artillery technique throughout the war in any weather on any ground. The difference was that in some cases the crew could do it by itself, and in other cases infantrymen assistance was required.

That is the catch - the 500-600 kg gun can be rolled in the desired spot by a far smaller manpower required, and despite the circumstances.

 

[bf109xxl]

I'm not sure that Soviets were issuing the APDS shots back in ww2.

That is the catch - the 500-600 kg gun can be rolled in the desired spot by a far smaller manpower required, and despite the circumstances.

I haven't heard any particular complaints about rolling of 1000 kg guns. Again, the ZiS-3s successfully rolled behind the infantry throughout the war. And with a lighter carriage, I'm afraid, it is impossible to provide sufficient durability when towed by a vehicle/tractor.

 

[tomo pauk]

bf109xxl - neither of these is/was with a discarding sabot.

I haven't heard any particular complaints about rolling of 1000 kg guns. Again, the ZiS-3s successfully rolled behind the infantry throughout the war. And with a lighter carriage, I'm afraid, it is impossible to provide sufficient durability when towed by a vehicle/tractor.

I also haven't heard any complaints.
I don't recall me suggesting that the ZiS-3 should've been outfitted with a lighter carriage, either.

 

[bf109xxl]

bf109xxl - neither of these is/was with a discarding sabot.

Armor-piercing discarding sabot (APDS) is a type of spin-stabilized kinetic energy projectile for anti-armor warfare. Each projectile consists of a sub-caliber round fitted with a sabot. The combination of a lighter sub-caliber projectile with a full-caliber propellant charge allows for an increase in muzzle velocity compared to full-caliber rounds, giving the round increased armor-penetration performance. To further enhance their armor-penetration capabilities, APDS rounds typically feature a hardened core made from tungsten or another hard, dense material.
The design of the BR-XXXP projectiles fully meets this definition.

I also haven't heard any complaints.
I don't recall me suggesting that the ZiS-3 should've been outfitted with a lighter carriage, either.

Alternative guns weighing 500-600 kg would only be able to be rolled by hand. Or, at best, by horse.

 

[tomo pauk]

Armor-piercing discarding sabot (APDS) is a type of spin-stabilized kinetic energy projectile for anti-armor warfare. Each projectile consists of a sub-caliber round fitted with a sabot. The combination of a lighter sub-caliber projectile with a full-caliber propellant charge allows for an increase in muzzle velocity compared to full-caliber rounds, giving the round increased armor-penetration performance. To further enhance their armor-penetration capabilities, APDS rounds typically feature a hardened core made from tungsten or another hard, dense material.
The design of the BR-XXXP projectiles fully meets this definition.

I know what is the APDS. The 'DS' part means 'discarding sabot' - ie. sabot falls after the shot leaves the barrel, while the core continues towards the target.
The AP shots made by the Soviets were not APDS, since the sabot and core were travelling together until the impact happened. Same as the German PzGr 40 shots and American HVAP.

Alternative guns weighing 500-600 kg would only be able to be rolled by hand. Or, at best, by horse.

I have no problems with historical guns being transported by motor transportation as well. YMMW.

 

[bf109xxl]

I know what is the APDS. The 'DS' part means 'discarding sabot' - ie. sabot falls after the shot leaves the barrel, while the core continues towards the target.
The AP shots made by the Soviets were not APDS, since the sabot and core were travelling together until the impact happened. Same as the German PzGr 40 shots and American HVAP.

Although the definition doesn't specify exactly where the sabot should separate, I agree that the more correct term would be "armor piercing composite rigid". But that doesn't change the point.

I have no problems with historical guns being transported by motor transportation as well. YMMW.

For an anti-tank gun, the ability to be moved by the crew is not important. Much more important (if not crucial) is the possibility of high speed transportation by vehicle/tractor. On the position, the ability to turn the gun will be important, which will be determined by the recoil force and the design of the recoil devices - and the lighter the latter are, the more the recoil spades will be buried in the ground and the harder it will be to turn the gun.
The same applies to the weight of the carriage: the lighter the carriage, the lower the speed at which the gun can be towed at the same weight of the gun barrel, etc.
The optimization criteria for anti-tank and light infantry support guns are quite different.

 

[tomo pauk]

Although the definition doesn't specify exactly where the sabot should separate, I agree that the more correct term would be "armor piercing composite rigid". But that doesn't change the point.

It certainly changes the point.
The APCR will be loosing the speed faster because it is a full caliber projectile all the way until it reaches the target.
The APDS will be loosing speed at the lower rate, since the sabots are discarded already within meters from the muzzle. Net effects are that the remaining part of the projectile (the core) will had a flatter trajectory and will reach the target faster (= much improves the chance to hit, especially against the targets that are further away and/or are moving), and that armor-piercing performance will be improved since the target will be hit with a faster projectile.

The definition of the APDS, that fails to state that the sabot immediately starts separation from the core after the complete projectile flew out from the muzzle, is a bad definition.

The optimization criteria for anti-tank and light infantry support guns are quite different.

Very true.

 

[bf109xxl]

it penetrate at around 900 meters what the 37mm could do at 400 meters.

Armor penetration does not refer to the gun, but to the gun/ammunition combination, and is highly dependent on the angle at which the projectile meets the armor. In addition, armor penetration will also be determined by armor parameters - at a minimum, hardness, viscosity and how hardness/viscosity varies with thickness. Therefore, the optimization criteria were also different for German and Allied artillery projectiles. The Germans needed to provide high armor penetration of inclined armor, while the Soviets needed to penetrate armor rather at low angles. For German AP projectiles, normalization at the moment of penetration was already achieved by the use of either non-uniform hardening or welding a high hardness cap on (a big surprise for the Soviets in 1941), while for the Soviet AP projectiles, optimization of the shape (break off grooves) was required.
It was absolutely unrealistic to foresee all armor changes (thickness, thermal treatment, mounting angles) before the war. Therefore, it was impossible to avoid rearmament during the war. There was not so much sense in optimizing pre-war AT guns. Thus, thee Soviets had to improve projectiles for the existing 45-mm guns, while the Germans had to increase the caliber. For the Germans, the Soviet 57mm gun would be absolutely perfect, providing armor penetration against any Soviet tanks until the end of the war.
In fact, I believe the Germans had the most difficult task - there was too little information about the new Soviet tanks, which were still at the beginning of deployment, and their characteristics were clearly underestimated. Only the poor training of Soviet tankers, the low level of tank unit commands and the completely sub-optimal structure of the tank units compensated, unfortunately, for the insufficient power of the German AT guns in the period of 1941-1942.

 

[bf109xxl]

It certainly changes the point.

It doesn't change anything, since at the time APCRs provided a higher armor penetration than traditional armor-piercing projectiles anyway. In 1943, production of this ammunition was of the highest priority for Soviet industry.
And optimizing the projectile was probably more important task than possible improvements of the gun itself - that was the point.

 

[Shortround6]

The Germans had APCR shot in 1940-41. British don't get it until 1943 (2pdr with Little John) other nations get it when? I don't think the US 37mm ever got it.
APCR and APDS (1944?) were used to give smaller guns an extended life.
The big armies had thousands of smaller AT guns and replacing the entire gun and ammunition stock piles/supplies (and tow vehicles at times) was very expensive.
How widespread the cored ammunition was, was also variable. 5% of ammo supplies or 30%? Depends on time and gun.
Cored shot also depends on the supply of Tungsten Carbide which the Germans were very short of and it tended to fade from German supply fairly soon. They kept up supply for the 50mm guns as they were border line. The 37mm gun was not going to penetrate a T-34 or KV with cored shot unless very lucky and suicidally close. The 75mm AT guns worked without cored shot as did the 88mm guns.
Americans didn't have much in the way of cored ammunition even in the winter of 1944/45. What there was was reserved for the 3in/76mm guns. The Americans never issued a cored round for the 57mm AT gun.

I believe that only the Germans intentionally designed AT guns to use cored shot, the taper bored 28mm, 42mm and 75mm weapons.

 

[tomo pauk]

It was absolutely unrealistic to foresee all armor changes (thickness, thermal treatment, mounting angles) before the war. Therefore, it was impossible to avoid rearmament during the war. There was not so much sense in optimizing pre-war AT guns. Thus, thee Soviets had to improve projectiles for the existing 45-mm guns, while the Germans had to increase the caliber. For the Germans, the Soviet 57mm gun would be absolutely perfect, providing armor penetration against any Soviet tanks until the end of the war.

Well before the war, Germans were probably aware of the armor protection of the French new tanks, such was the R35 that was also exported. Prudent planing should probably involve the expectation that the even newer tanks will be with the improved armor protection, even if the 'only' improvement is increase of thickness. So having a more potent AT gun in the backburner is/was not unrealistic.

There was nothing stopping the Soviets to have the F22 outfitted with single-man elevation and azimuth controls, making it very effective in the AT role for the 1st 2 years of the Great patriotic war. Germans making their 75mm to be of modern layout (split carriage, appropriate sights & controls, hopefully the muzzle brake), paired with suitable ammo would've also relieve some of the pressure to have the improved AT guns. Basically a gun no worse than the pak 97/38, but at least 5 years earlier.

Yes, the Soviet 57mm ATG was something else. It will still require the tungsten to be available in order to kill the heaviest tanks, and tungsten was not something that Germans had in boatloads.

n fact, I believe the Germans had the most difficult task - there was too little information about the new Soviet tanks, which were still at the beginning of deployment, and their characteristics were clearly underestimated.

As above, Germans became aware of the bad state of their mainstay guns wrt. armor piercing more than a year before they faced the new Soviet tanks.

It doesn't change anything, since at the time APCRs provided a higher armor penetration than traditional armor-piercing projectiles anyway.

APCRs always provided the higher armor penetration than the traditional AP ammo, not just at the time.

For the 1943:
Perhaps 90% of the Soviet guns tasked to kill tanks were still unable to kill the heavy German tanks in 1943 at the normal combat distances (the 10% being the 122 mm long guns, 85mm AA guns and the 57mm gun) despite the APCR ammo, so having the APDS would've helped, and thus changed the situation.
Situation for the Soviet tanks was not helped by the superiority of the widely-available German long 75mm guns+ammo+sights (even after removing the Panther's gun from this equation), that enabled the Germans to successfully engage the Soviet tanks from long distance, from where the Soviet tanks were ill able to reciprocate. Add in the better way the Germans handled their tank units, and there is no wonder that Soviets were suffering the loopsided kill/loss ratio.

 

[bf109xxl]

The 37mm gun was not going to penetrate a T-34 or KV with cored shot unless very lucky and suicidally close.

It is not true. At least the T-34 could be penetrate by 37mm German projectiles into the side - it happened quite frequently. There are some statistical data for the period of the Battle of Moscow. 21 out of 83 studied KV and T-34 had through or dangerous armor penetrations from 37-mm. In addition, 31 tank had penetrations from projectiles of unspecified caliber, a considerable part of which may be 37-mm.

 

[Shortround6]

It doesn't change anything, since at the time APCRs provided a higher armor penetration than traditional armor-piercing projectiles anyway. In 1943, production of this ammunition was of the highest priority for Soviet industry.
And optimizing the projectile was probably more important task than possible improvements of the gun itself - that was the point.

The huge difference was that the APCR shot offered higher performance (armor penetration) and relatively short ranges. This is some what caliber dependent. The larger the caliber the longer the distance the APCR shot has an advantage over normal shot.
For the German 37mm the crossover point was around 400 meters, ie, at over 400meters the normal full bore shot penetrated more armor.
For the Soviet 45mm M1942 the distance was close to 900 meters (depends on slope and source).
The 75/76mm guns had cross over points in excess of 1000 meters and were running into other problems, like greater dispersion.
If you only have 2-4 "super" rounds in the rack and they are less accurate do you fire them at long range try to destroy the enemy at a distance or do you hold fire for a better chance of hit?

Better projectiles could and did improve performance but for most nations outside of Germany practical cored ammo only showed up in 1943.
France actually had some in 1940 but in very small quantities and in guns that had rather dismal performance to being with.