Alternative light and anti-tank guns, 1935-45

tomo pauk said:

- 88mmL56 gun on the 10.5cm howitzer carriage - far less clumsy than the Pak 43, but main advantage is that it can be done fairly early, like before ww2. If Goering is against this, see what can be agreed with the Navy. It should also make the alt-Nashorn being a lower target, FWIW.
- 7.5cmL70 gun on the 10.5cm how carriage - sorta German 17 pdr for all intents and purposes.

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Nope and nope.

The 88mmL56 gun in the Tiger went 1332kg including muzzle brake. The poor 10.5cm howitzer carriage is not going to stand up to that.

The 7.5cmL70 gun was about 1086kg.
The 17pdr gun was about 827kg (being around 1.5 meters shorter helped)

Not saying you can't develop a towed mount for either gun, but the standard 10.5cm howitzer carriage is not going to be a short cut.

Edit. Let's remember that the very early 17pdr on the 25pdr carriage could only aim about degrees each side without using the turntable.
Trying to point one of these high power guns 20-30 degrees off axis was not going to end well.

Good points. A few comments:

Shortround6 said:

The whole idea of using capped shot is that uncapped shot tends to shatter/break up with impacts approaching 2500fps/ 750mps but this depends on the armor and the heat treatment of the projectile.
You can use capped shot at impact velocities of around 3000fps/900mps but after that you tend to need Tungsten.

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Yes. You can fit a cap to an APCR projectile as well?

Please note that 57mm AT guns had a velocity of round 4000fps and needed tungsten to work. Also note that APDS core made of tungsten weighed a lot more per unit of frontal area than a steel projectile and would retain velocity better.

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During the cold war the Soviets made APFSDS projectiles using steel as an alternative to tungsten or depleted uranium. Not sure if these were used by the Soviets themselves or was it only for export customers? And to be fair, these used a variety of steel that was invented after WWII, so called "maraging steel". But still, very high velocity compared to anything during WWII.

As for the density of steel vs tungsten, yes I'm aware. Either you need to make the penetrator thicker to compensate, or then you'll have to live with poorer ballistics.

re

z42 said:

You can fit a cap to an APCR projectile as well?

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Yes. In fact, most (I think) post-war APCR and APDS were fitted with piecing caps of one form or another. Some of the modern APFSDS also have piercing caps as well.

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z42 said:

During the cold war the Soviets made APFSDS projectiles using steel as an alternative to tungsten or depleted uranium

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The early 115mm APFSDS used the ~equivalent of T2 tool steel, a form of cutting steel widely used in machining.

Shortround6 said:

Nope and nope.
The 88mmL56 gun in the Tiger went 1332kg including muzzle brake. The poor 10.5cm howitzer carriage is not going to stand up to that.
The 7.5cmL70 gun was about 1086kg.
The 17pdr gun was about 827kg (being around 1.5 meters shorter helped)
Not saying you can't develop a towed mount for either gun, but the standard 10.5cm howitzer carriage is not going to be a short cut.

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That would be 'yes and yes'.
The Pak 43 started out using the carriage of the 10.5cm howitzer + the wheels of the 15cm howitzer. The ordnance as installed on the Tiger II weighted 2265 kg, with just the barrel weighting 1155 kg. A far easier set-up would've been if the gun in question is the smaller and lighter 'Tiger's gun', let alone the 'Panther's gun'.

Shortround6 said:

Edit. Let's remember that the very early 17pdr on the 25pdr carriage could only aim about degrees each side without using the turntable.
Trying to point one of these high power guns 20-30 degrees off axis was not going to end well.

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I will not try and suggest that Germans revert to using a 1-legged carriage that many years after the ww1.

z42 said:

IIUIC these were never made in numbers, so there was never a big batch of them available for conversion into AT guns.

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They might've been much more than the footnote that the Dickermax and Sturer Emil were. As well as being in the frontline already in 1939.

Germans can also impress the captured heavier (70+ mm) AA guns into the AT role. Be it as-is (lighter guns preferably), or outright converted into the AT guns.

z42 said:

I think the undoing of all these is the weight. A Stug III cost about 6 times as much as a PAK 40, not including the prime mover. Yes, fewer barrels for the same price, but might be a better investment as the better mobility and protection makes it more likely to survive for the next day?

As a slight aside, the 75L70 was pretty good. Smaller and cheaper than the 88L56, yet better penetration. Good enough for practically anything armored it was going up against for the entire war.

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Yes, once past some weight limit the AT guns become as much as an asset as they are a liability. IMO, the price comparison should include a cost of the prime mover, and the heavy AT guns will require a potent prime mover - these don't come in cheap, and will still be problematic to be used on a terrain that can combine slopes with snow or mud.

One of the reasons the 75L70 was cheaper was because it's barrel life was lower by factor of 3(!). At the distances we might require the busting of enemy tanks by these heavy guns (beyond 1000m), the penetration advantage of the 75L70 went down under single digits in %, and the 88mm was more accurate if both guns were using the APCR ammo.
(bigger HE shell that 88mm had was probably of tertiary importance for an AT gun)

Probably the main advantage of the 75L70 was that it was very compact (or it was that the Tiger's gun was too voluminous?, enabling it to be installed into a smaller turret.