Alternative light and anti-tank guns, 1935-45

[Shortround6]

The Panzer IV, with it's short barrel (28 caliber) 7.5 cm gun, was intended to fire slow (385 m/s) HE shells against infantry targets.

This may be a misconception? The Pz IV was not intended to support infantry. It was intended to support the Pz III tanks when they ran into things that gave them trouble. Actual low production of the Pz III forced much larger numbers of Pz Is & IIs to see combat and the Pz IV had to shoulder more of the load. Pz IV was also supposed to fire smoke to screen the other tank units and accompanying infantry. The HE was to try to silence AT guns and fortifications, like pillboxes and trenches. Maybe these are infantry targets. Pz IVs were give some AP for when the Pz IIIs were not close. In the BoF the PZ IVs were often supporting Pz IIs with 20m guns and they had to do more tank fighting than had planned on in 1938-39.

The solution came with HEAT charges. With those, speed of the shell was no more a factor (a lower speed was even better) and even a short barreled howitzer became an effective AT gun. See, IE, the 75/18 model 34 Italian howitzer, that became the main gun of the Semovente 75/18 self-propelled gun.

A lot depends on what is meant by effective AT gun. Obviously making a hole in the target is the first thing. Hitting is pretty much the second thing and here both the PZ IV and the Semovente start running into problems. They have a short effective range. The Pz IV more so. The low velocity means a very curved trajectory due to the long time of flight. Effective range (chances of getting first round hit) may be between 400-500 meters unless the crew is very skilled. Shorter range for the German gun. A German Pak 40 might have an effective range almost double. If you are trying to fire at over 1000meters the Pak 40 might take 1-3 misses to get on target, the Low velocity rounds can take several more.
This has nothing to do with how many rounds the guns can put into a certain size target at a certain range and everything to do with estimating (guessing) how far away the target is, how far off the 1st shot went and what is needed to correct things. Now we get away from the gun and sight itself and into who is tracking the shot (looking at the tracer?) and this man's ability to see where the round/s are going and give corrections to the gunner.
This also assumes both guns/tanks are stationary. Lobbing shells out that take 3 seconds to arrive instead of 2 seconds can really affect things shooting at even a slow-moving target.

 

[Dogwalker]

But the OP is about Light Anti Tank guns.

And that's the solution.

The 10.5 cm Leichtgeschütz 40 recoiless rifle.

As stated above, HEAT charges changed the terms of the equation. The penetration capability of the projectile was no more given by the speed, but by the the diameter.
The 105mm recoiless rifle weighted only about 400 kg (less than half than the 2pdr), but threw a 14kg HEAT projectile at 373 m/s, or a HE projectile at 336 m/s (values not that different than those of the 76mm howitzers), with a penetrating capability of the HEAT charge superior to that of any 75mm AP projectile, and indipendent from the inclination of the armor.

 

[Dogwalker]

A lot depends on what is meant by effective AT gun. Obviously making a hole in the target is the first thing. Hitting is pretty much the second thing and here both the PZ IV and the Semovente start running into problems. They have a short effective range. The Pz IV more so. The low velocity means a very curved trajectory due to the long time of flight. Effective range (chances of getting first round hit) may be between 400-500 meters unless the crew is very skilled.

It's more a theoetical problem than a real one, Reports of the Russian front tells tanks were practically never engaged at long range. Apart that it was often a lot complicate to even see them past those 400-500m, the 75mm AP rounds were effective against a T34 only practically at point blank.

 

[tomo pauk]

Apart that it was often a lot complicate to even see them past those 400-500m, the 75mm AP rounds were effective against a T34 only practically at point blank.

75mm AP rounds fired from what guns?

 

[Dogwalker]

75mm AP rounds fired from what guns?

This is really interesting. It's a report of the Italian 120° artillery regiment of a battle they fought on late July 1942 near Serafimovic. Serafimovich, 30 e 31 luglio 1942
It's interesting because they used guns of various calibers and, among those, both AP and HEAT charges, both the German 7.5 cm PAK (here called 75/97/38) and the Italian 75/32.
...
2) At ranges greater than 500 metres NO PROJECTILE HAS ANY REAL EFFICIENCY – useful range for anti-tank shots is from 50 to 300 metres.
...

 

[tomo pauk]

This is really interesting. It's a report of the Italian 120° artillery regiment of a battle they fought on late July 1942 near Serafimovic. Serafimovich, 30 e 31 luglio 1942
It's interesting because they used guns of various calibers and, among those, both AP and HEAT charges, both the German 7.5 cm PAK (here called 75/97/38) and the Italian 75/32.
...
2) At ranges greater than 500 metres NO PROJECTILE HAS ANY REAL EFFICIENCY – useful range for anti-tank shots is from 50 to 300 metres.
...

That you for the excerpt.
By mid-1942, the best German 75mm guns were the Pak 40 and Kwk 40, both far more capable than the Pak 97/38 or the Italian Army 75mm guns, and more than capable to handle the T-34s beyond 1000 m.

 

[Dogwalker]

That you for the excerpt.
By mid-1942, the best German 75mm guns were the Pak 40 and Kwk 40, both far more capable than the Pak 97/38 or the Italian Army 75mm guns, and more than capable to handle the T-34s beyond 1000 m.

Have we some excerpt that tell of consistent (not anecdotes of a pair of lucky shots) beyond 1000m kills of tanks of any kind by those guns?

 

[tomo pauk]

Have we some excerpt that tell of consistent (not anecdotes of a pair of lucky shots) beyond 1000m kills of tanks of any kind by those guns?

IMO, the reputation of the Pak 40 is well established. I don't have stories at this moment, but I have the 'Panzerbeschusstafel' for it, from the Waffen Revue #82. Says that T-34 can be destroyed with APHE shot (PzGr 39) at turret front under 1000m, and sides and rear under 1500-1800m, depending on the version. Glacis plate on the early T-34s is the best armored part of the tank per the table, apart from the driver's cover plate, that is susceptible to the hits at under 500m.
Shots with APCR (ie. PzGr 40) yield the same or even worse results.

 

[Elan Vital]

That you for the excerpt.
By mid-1942, the best German 75mm guns were the Pak 40 and Kwk 40, both far more capable than the Pak 97/38 or the Italian Army 75mm guns, and more than capable to handle the T-34s beyond 1000 m.

It depends what is hit. The turret is not particularly thick or angled, nor are the sides so defeat at 1km and more is possible.

The hull front is a notably tougher target, owing to the efficiency of steep angles against fullbore projectiles (same goes for small hatch Sherman). As a result the velocity for guaranteed penetration with a 75mm gun is 734 m/s ( a bit under 500m for a KwK/PaK 40) and the limit at which no backface deformation occurs is 670 m/s (1000m). So a T-34 hull front against a KwK/PaK 40 is very fair game up to a bit beyond 500m but penetration probability reduces to near-0 at 1km.

For 75mm guns weaker than KwK/PaK 40, such distances would be notably reduced, though the sides and turret would remain good targets.

Edit: pretty much matches up with your recent post

 

[tomo pauk]

It depends what is hit. The turret is not particularly thick or angled, nor are the sides so defeat at 1km and more is possible.

The hull front is a notably tougher target, owing to the efficiency of steep angles against fullbore projectiles (same goes for small hatch Sherman). As a result the velocity for guaranteed penetration with a 75mm gun is 734 m/s ( a bit under 500m for a KwK/PaK 40) and the limit at which no backface deformation occurs is 670 m/s (1000m). So a T-34 hull front against a KwK/PaK 40 is very fair game up to a bit beyond 500m but penetration probability reduces to near-0 at 1km.

See post # 368

For 75mm guns weaker than KwK/PaK 40, such distances would be notably reduced, though the sides and turret would remain good targets.

Of course.

 

[Dogwalker]

So we passed from 500m to a bit beyond 500m

 

[tomo pauk]

So we passed from 500m to a bit beyond 500m

We did not.

 

[Dogwalker]

So a T-34 hull front against a KwK/PaK 40 is very fair game up to a bit beyond 500m

 

[tomo pauk]

So a T-34 hull front against a KwK/PaK 40 is very fair game up to a bit beyond 500m

See post #368.

 

[Shortround6]

I thank you for that account of the battle.
What it shows is subject to interpretation, but the Italian gunners showed bravery and determination using mostly non-antitank guns against tanks.
The 97/38 was an expedient gun and is basically a French 75 field gun as far as ballistics goes. It is pretty much what the T-34 was designed to deal with. That is 75-76mm field artillery with HE rounds. Taking out the fuses is only going to help a little bit.
What happened was pretty much what was expected.
Low velocity guns don't do well against armor.
Taking out the fuses from HE shells (or not fitting them) is only going to work against a restricted range of armor. That is armor that is too thick for an HE shell exploding on contact to damage much inside the tank but thin enough for the inert HE shell to get through the armor. The HE shell is made of softer steel, not pointed (pretty much flat with the fuse removed?) and lighter than a proper AP round.
The lack of effect for the hollow charge rounds is notable. They need to hit in a favorable location to have effect inside the tank. Bad fuses or shell explodes with the hollow charge is turned away from the sloped armor? The proving ground penetration figures do not seem to be achieved in battles. Note that hollow charge rounds have real problems with things added to tanks, like tool boxes and storage bins and any extra stuff that crews might add on. Hollow charge shells were not the panacea some people thought. For low velocity guns they were just the least worst option.

The low velocity guns have trouble hitting at 500meters and above due to curved trajectory. That is well known. Trying to hit in specific locations, like tracks, gets harder at long ranges.
Trying to hit low points on tanks, like tracks gets harder with range. Battle fields are not flat, at longer ranges many times the gunners can only see the top 1/2 or 2/3rds of the tank.
at longer ranges against moving tanks the low velocity guns have to lead the tank by a greater amount. All of this was known before the War and was the reasoning for actual AT guns.
I would also note that many field guns do not have a sight with much, if any, magnification.

an example of the 100/17 used by some units in the action in the article. Only 6 degrees of traverse without shifting the gun.

There are 3 things wrong with it when trying to use it as an AT gun.
Trying to say that using ill-suited guns and poor ammo as arguments against purpose built AT guns with proper shells and the ranges they could engage at is not right.
I will say that some armies (looking at the British here) used cheap, far from optimum projectiles in their AT guns for several years in WW II.

 

[Dogwalker]

Note that hollow charge rounds have real problems with things added to tanks, like tool boxes and storage bins and any extra stuff that crews might add on.

Not necessarily. The distance the charge of a HEAT projectile explodes from the armor is amost never optimal. It's limited by the maximum length of the projectile, but in reality, if the projectile can explode a little further from the armor, that allows the jet to form more completely and to penetrate more. To add, in front of the armor, something that's not armor, can even worsen the situation for the crew.

Battle fields are not flat,

And that's why tanks were practically never engaged at long range by Infantry AT guns.
"Have we some excerpt that tell of consistent (not anecdotes of a pair of lucky shots) beyond 1000m kills of tanks of any kind by those guns?"

 

[Shortround6]

Not necessarily. The distance the charge of a HEAT projectile explodes from the armor is amost never optimal. It's limited by the maximum length of the projectile, but in reality, if the projectile can explode a little further from the armor, that allows the jet to form more completely and to penetrate more. To add, in front of the armor, something that's not armor, can even worsen the situation for the crew.

This is true, but this is why HEAT projectiles give rather inconsistent performance in the real world. The projectile may hit something that makes it detonated and better distance or angle, or it may detonate at a worse angle or worse distance. The same can be said of a chunk of steel moving at high speed but the variation in effect on the armor is often less.

And that's why tanks were practically never engaged at long range by Infantry AT guns

We may be running into problems with translation in language or with problems with definitions.
Original premise was light AT guns. Which is not the same as Infantry AT guns although there is some cross over. In the British army in 1939-40 the 2pdrs belonged to the Artillery. The Infantry had the Boys AT rifle and some rather ineffective rifle grenades and wanted something better. When 6pdr AT guns showed for the Artillery the 2pdrs were sometimes given to the Infantry but without giving the Infantry more men for gun crews this didn't work well. Some units got transferred. When 17pdrs showed up for the artillery AT gun batteries some 6pdrs wound up in infantry units.
Other Armies did things differently. British were a little wasteful. Giving 1 ton 40mm AT guns to the infantry with no HE ammo meant that the 2pdr guns had very little to shoot at unless enemy tanks showed up. Some armies tried to make Infantry guns that fired HE for support and gave them a few AP shells incase a few enemy tanks showed up. Some armies issued actual small AT guns and gave them HE shells so they could do something else when there were no tanks fighting them on some days.

An Infantry AT gun is, somewhat by definition, a small low powered gun of limited effective range against tanks. Especially once tanks started using even 30mm armor. Giving infantry units old, obsolete WW I guns as Infantry guns and giving them a few (or 1-2 dozen) AT shells does not actually make them Infantry AT guns except to make higher up supply officers filling out tables of organizations happy.

To be even a decent AT gun there are things that the weapon has to do or have capability of doing.
1. Be able to pierce the armor of common enemy tanks and do lethal damage behind the armor.
2. Be able to do this at ranges long enough to stop the enemy from overrunning the infantry positions.
3. Have a decent rate of fire to engage several targets in a short period of time.
4. Have a wide traverse to allow engaging multiple targets without having to shift the entire gun.
5. Have a sight that allows for rapid target acquisition and a control system (traverse and elevation) that allows for rapid engagement. AT guns, except for very large ones had one man aim, travers and elevate. Many field guns used one man for aiming and elevating and a separate man for travers which requires a lot of teamwork/coordination for fast shooting against moving targets.

Unfortunately for the Infantry, a lot of times what they got were not purpose built AT guns or even purpose built infantry support guns but cast offs from the Artillery that they didn't want any more but were in good enough condition that nobody (accountants) wanted to scrap them.

A bit long winded here, but I am not done.
Actual AT guns, are supposed to engage enemy tanks at less than overrun distances, if the terrain allows it.
Actual AT guns have the velocity to allow for trajectories that allow for a decent percentage of hits at 500-1000 meter (and sometimes beyond).
Actual AT guns have enough penetration to allow for successful penetration most of the time at these ranges.
Actual AT guns have a sight system (telescope) that allows for successful engagements at these distances or longer.
Yes, many times the terrain or weather does not allow for long range engagements but if you don't plan for or equip your troops with longer range equipment you are often going to fail when having to fight at 500-1000meters (or longer)

The Account of the Italian unit action shows or mentions 6 different guns used. The type of 20mm is not mentioned, 20mm AT rifle or 20MM AA gun. Of the other 5 guns only the 4 (?) 75/97/38s are actual AT guns. All the others are actual artillery guns that were being used as forward deployed emergency AT guns because the Italian army didn't have any AT guns or at least not good ones.
Using 10cm howitzers and indeed 10.5cm field guns at front line AT guns is desperation. A 3 ton limited traverse, long range 10.5cm gun in NOT an infantry gun.

 

[Dogwalker]

We may be running into problems with translation in language or with problems with definitions.

A more restricted definition doesn't help in the slightest when the only pieces that seem to have, on paper, some effectiveness at long range seem to be the most modern 75mm guns, that are also the heaviest AT pieces infantry can reasonably manage (for the PAK 40 we are talking of 1,425 kg) and still we are lacking of "some excerpt that tell of consistent (not anecdotes of a pair of lucky shots) beyond 1000m kills of tanks of any kind by those guns".
Instead of complaining about the excerpt posted, it could be maybe the case to find something better.

 

[Shortround6]

Basically the Italian gunners (and commanders) were trying to do the best they could in very bad situation.
The Italians never really made a new/more powerful AT gun than the 47/32.

While it was a good combined infantry gun/anti-tank gun in 1938-1940 it was past it's sell by date in 1941.
It came apart for easy transport. It fired a useful HE shell, especially compared to other counties 37mm AT guns.
But it had no shield to protect the gunners from both HE shells (shorts, a directed didn't matter even if a gun had shield) and from machinegun fire.
It also had been out classed by tank armor in 1941.
Trying to use old mountain howitzers like the 65/17, even with HEAT rounds was not a real solution. The 'solution' being used in Russia was even worse. Even larger, more powerful field artillery guns being used as AT guns because the Italian army didn't have any AT guns that could deal with the T-34 in an efficient manner.
The 10.5/32 was an extreme example

Please note than when moved by horses the barrel was pulled out an carried on a separate wagon with its own team of 6 horses. Ammo was moved by another wagon?
These are not infantry guns. These are not AT guns. They are guns of desperation used by desperate men.

To be fair, neither was the British use of 25pdrs. They used them, they knocked out German tanks, but it was a poor use the guns. British spent a lot of time/effort into giving the 25pdr some anti-tank capacity, at least one projectile in service, one or more projectiles in development. Two different rounds (AT rounds were had projectiles crimped place for faster loading) and the development of the muzzle brake to handle the later super charge hi-velocity load.
All to cover up the fact that they went cheap on the 2pdr with the standard AP round and that they were late with the 6pdr which as an AT gun, beat the stuffing out of the 25pdr in just about every category.
If your field guns are in the forward lines playing at being AT guns they are not doing field gun work. Laying down HE fire and smoke as needed or firing illuminating rounds at night.
Plenty of British tanks were destroyed in North Africa by towed AT guns at ranges over 1000 yds/meters that were not 88mm guns.

 

[Dogwalker]

Basically the Italian gunners (and commanders) were trying to do the best they could in very bad situation.

But I'm not talking about them.
This is not a thread about Italians only because the only excerpt we have read until now about the reality of AT gunnery on the Russian front happens to be Italian.
Have we "some excerpt that tell of consistent (not anecdotes of a pair of lucky shots) beyond 1000m kills of tanks of any kind by those guns" MADE BY ANYONE?
If we have, then the AT tanks were effective at those distances. If not, we are only talking about performances on paper and ignoring the reality of battelfields.