WI: The Carro Armato P 26/40 enters service in 1940?

[Nell_Lucifer]

For those who don't know what I am talking about, the P 26/40 was Italy's WW2 'heavy tank' that came too late to make any important contribution to the war, ending up post armistice as turret-bunkers. In truth, the tank was more comparable to a Panzer IV G, Sherman M4A1, T-34 1940 etc. than any heavy tank.

Now, I know that this type of scenario, in which you snap your fingers and suddenly X nation gets Y vehicle Z years earlier, somehow, has the problem of, well, going through the steps that lead to said vehicle being needed or being able to exist... and I have a justification for why this tank could exist/the conditions that it might allow it to exist.

Let's suppose that in 1936-37 after the Souma S35 entered service, the Italian military got their hands on some detailed photos of the tank and grew concerned at its capabilities. (40 km/h speed, 47 mm armor, 47 mm anti-tank cannon etc.) After all, France is Italy's rival at this point in time so it makes sense for them to watch what the French are doing and by chance or not, Mussolini ends up very much not impressed when he sees the new Italian 'medium tank' being built by Ansaldo compared to the already in production French S35. As such, he ends up asking for a better armored, armed and plainly more powerful tank than the S35, one that can fight said tank at 1 kilometer (usual range of the day).

While I don't see this having any major impact on the war, I wonder if it might have an impact on some battles in North Africa or in Italy in 1943.

Another thing to consider is that the P 26/40 offers a more easily upgrade-able platform than the M13-15 series of tanks, which, I think, post 1941 would receive a 3 man turret with the more powerful 75/46 cannon that is comparable to the PaK 40 and perhaps more armor (up to 80 mm compared to the 50 like the Panzer IV H?)

(And for those who will ask, what doesn't get build I would lean towards the M13 'medium tanks' as, by the time they finished the P 26 and M 13, the Italian military will easily notice how every other country is building bigger, more armored and faster 'medium tanks' and 'heavy tanks' - Cruiser Tank Mk IV, Panzer III & IV, M2A4 Stuart - Perhaps they will go for an earlier M16/43 cruiser tank in 1941)

 

[alspug]

It is entirely possible for a larger and better tank to make it into Production, the problem is that your production numbers will be absmal. It is the equivallent in terms of production capacity used up as the King Tiger is to the Germans. So instead of 200 M13 variants you get maybe 20 to 30 P 26.

Italian Industry was capable of producing designs as good as any country in the world, the problem was the industrial capacity of what was a fairly poor country was terrible. Now if the Libyan Oil was found and producing and Italy stayed Neutral then yes the production capacity would have improved.

 

[GuildedAgeNostalgia]

If put under Rommel's command, they could make a difference in North Africa, although I doubt it'd be enough to get Rommel to the Nile.

 

[CaptainCalvert]

A better tank design is not too difficult to develop, but it probably reduces the number of tanks as noted. The harder bit is to justify a long 75.
In 1939 and 1940 all the 75mm and 76mm were low velocity HE throwers (German 75 L24 in panzer IV and Neubaufahrzeug, French Char 2C, KV1 and early T34). The long 75/76 was a fairly late development.
The 47 to 50mm class was in service or under development and the 57mm on its way. The Italian 47 was more or less as good as anyone elses's tank mounted gun, so unless they realise they will be facing Char B and Matildas they will worry a bit about the S35, but otherwise think they can cope.
The easiest line is to start with an uprated 47, inspired by the Czech, French or Belgian 47 AT guns - likely a shortened version rather than trying to fit full sized into a turret.
This makes sense if they are making an uparmoured tank as they would asdume others will do so too and need a gun to deal with these.
These will do fine in 40 and 41 apart from matildas which will be a bit tough. Some time in 42 or so, they'll want good AP and bigger HE so the long 75 pops up, - cue 75mm armed p26 but with 2 man turret to squeeze it in.
Probably a few flaws in there but no giant leaps.

 

[tomo pauk]

This will push the British to start installing proper cannons on their tanks.

 

[Fire and shadow]

In 1939 and 1940 all the 75mm and 76mm were low velocity HE throwers (German 75 L24 in panzer IV and Neubaufahrzeug, French Char 2C, KV1 and early T34). The long 75/76 was a fairly late development.

Did the T-28/35 not have a similar 76mm gun to the early T34?

 

[CaptainCalvert]

This will push the British to start installing proper cannons on their tanks.

They didn't need pushing. They ran out of equipment and couldn't afford to stop making the 2pounder to produce the 6 pounder [1]. It would also have helped if other factories could make 2 pounder shot so they could bring in capped rounds in 41, thus forestalling the problem with face hardened armour.

[1] there is of course the question over why they weren't already tooled up for the 6 pounder AT gun by 1940.

 

[CaptainCalvert]

Did the T-28/35 not have a similar 76mm gun to the early T34?

How could I forget the T28 and T35?
Multi turreted tanks are awesome. And not that good really.
And yes they did have a short 76.

 

[alspug]

Did the T-28/35 not have a similar 76mm gun to the early T34?

The intial Soviet L-11 76.2mm guns L30 had low velocity (612ms)but still higher than the German 75mm L24(380ms).
The Later Soviet 76.2mm F-34 was a 42.5 Calibre (680ms). THis is equivallent to the German L43 and L48 guns. The Soviets had a reputation of getting higher MV out of any given gun calibre.

 

[CaptainCalvert]

The intial Soviet L-11 76.2mm guns L30 had low velocity (612ms)but still higher than the German 75mm L24(380ms).
The Later Soviet 76.2mm F-34 was a 42.5 Calibre (680ms). THis is equivallent to the German L43 and L48 guns. The Soviets had a reputation of getting higher MV out of any given gun calibre.

The sources I've seen show T28 and T35 had L10 23 calibre guns, though very early T28 had 16 or 16.5 calibre ones.
The early L11 in the T34 and KV1 were a bit better but still fairly low velocity.
Like the Russians, the Italians could well have started with a 65 or 75mm as a decent HE gun with limited AT performance then developed it to a longer better AT weapon.

 

[cortz#9]

A better tank design is not too difficult to develop, but it probably reduces the number of tanks as noted. The harder bit is to justify a long 75.
In 1939 and 1940 all the 75mm and 76mm were low velocity HE throwers (German 75 L24 in panzer IV and Neubaufahrzeug, French Char 2C, KV1 and early T34). The long 75/76 was a fairly late development.
The 47 to 50mm class was in service or under development and the 57mm on its way. The Italian 47 was more or less as good as anyone elses's tank mounted gun, so unless they realise they will be facing Char B and Matildas they will worry a bit about the S35, but otherwise think they can cope.
The easiest line is to start with an uprated 47, inspired by the Czech, French or Belgian 47 AT guns - likely a shortened version rather than trying to fit full sized into a turret.
This makes sense if they are making an uparmoured tank as they would asdume others will do so too and need a gun to deal with these.
These will do fine in 40 and 41 apart from matildas which will be a bit tough. Some time in 42 or so, they'll want good AP and bigger HE so the long 75 pops up, - cue 75mm armed p26 but with 2 man turret to squeeze it in.
Probably a few flaws in there but no giant leaps.

The Czechs had a long barreled 75mm AA gun in 1937 the 7.5 Kanon PL vz. 37.

The Germans sold some of the surplus guns to Italy and Finland but apparently and surprisingly didn't keep the gun in production for their own use.

 

[tomo pauk]

The intial Soviet L-11 76.2mm guns L30 had low velocity (612ms)but still higher than the German 75mm L24(380ms).
The Later Soviet 76.2mm F-34 was a 42.5 Calibre (680ms). THis is equivallent to the German L43 and L48 guns. The Soviets had a reputation of getting higher MV out of any given gun calibre.

Soviet 76.2mm guns as used on tanks/AFVs or as field guns were not equivalents of the German L43 and L48 guns, when it is about the muzzle energy. German guns used cartridges with much more propellant (about 10-15% less than what 8.8 cm L56 used), making them have greater muzzle velocity. IOW, the best Soviet 7.62 AP shot for the F34, the 3kg APCR, was with MV of 950 m/s, while the best German APCR for the L43 and L48 was 4.1 kg heavy, with MV of 930 m/s. End result being that the German gun was capable for greater armor penetration.
The 7.5cm Pak L46 was even more powerful, with almost the same weight of propellant as the 8.8cm L56, managing 990 m/s with the 4.05 kg APCR.

There was no Soviet gun equivalent to the even more powerful guns like what the Panther had, or the British 17 pdr (these have had about 4 kg of propellant, compared with 2.2-2.5 kg on the 7.5cm L43 and L48, or 2.7-2.8 kg for the 8.8cm L56).

Soviets were experimenting with the tank/AFV gun that was using the powerful cartridge like the one from 7.62 AA gun (now that is equivalent of the L43, 46, 48 German guns, as well as British 77mm HV or the US 3in/76mm), but that was sidelined with 57mm (can fit on the T-34 easily, giving birth to the T-34-57) and 85mm (even better AP capabiities than that 7.62, as well as being a better HE thrower).

A gun that stands out wrt. great muzzle velocity in the Soviet arsenal was the 57mm AT gun, pusing the APCR to almost 1300 m/s (!).

The Czechs had a long barreled 75mm AA gun in 1937 the 7.5 Kanon PL vz. 37.
The Germans sold some of the surplus guns to Italy and Finland but apparently and surprisingly didn't keep the gun in production for their own use.

Germans have had the similar 7.5cm Flak in use; granted, it was out-shadowed by the 8.8cm.

 

[Nell_Lucifer]

It is entirely possible for a larger and better tank to make it into Production, the problem is that your production numbers will be absmal. It is the equivallent in terms of production capacity used up as the King Tiger is to the Germans. So instead of 200 M13 variants you get maybe 20 to 30 P 26.

Italian Industry was capable of producing designs as good as any country in the world, the problem was the industrial capacity of what was a fairly poor country was terrible. Now if the Libyan Oil was found and producing and Italy stayed Neutral then yes the production capacity would have improved.

I believe that the comparison between the P 26 to the King Tiger is quite exaggerated, yes, obviously the P 26 will be built in lesser numbers than the M13, but 20-30 instead of 200? I think it is more accurate to be between 120 to 150, after all, the P 26 is just a slightly bigger M13. (Here the initial prototype side by side with an M13/14)

A better tank design is not too difficult to develop, but it probably reduces the number of tanks as noted. The harder bit is to justify a long 75.
In 1939 and 1940 all the 75mm and 76mm were low velocity HE throwers (German 75 L24 in panzer IV and Neubaufahrzeug, French Char 2C, KV1 and early T34). The long 75/76 was a fairly late development.
The 47 to 50mm class was in service or under development and the 57mm on its way. The Italian 47 was more or less as good as anyone elses's tank mounted gun, so unless they realise they will be facing Char B and Matildas they will worry a bit about the S35, but otherwise think they can cope.
The easiest line is to start with an uprated 47, inspired by the Czech, French or Belgian 47 AT guns - likely a shortened version rather than trying to fit full sized into a turret.
This makes sense if they are making an uparmoured tank as they would asdume others will do so too and need a gun to deal with these.
These will do fine in 40 and 41 apart from matildas which will be a bit tough. Some time in 42 or so, they'll want good AP and bigger HE so the long 75 pops up, - cue 75mm armed p26 but with 2 man turret to squeeze it in.
Probably a few flaws in there but no giant leaps.

I want to point out that the Italians had in 1937 a long 75 in testing, specifically the Cannone da 75/32 (34 at this point in time) modello 37, which was a development and replacement of the 75/18 they already had in service, with the capabilities of anti-tank use.

OTL the Italian High Command rejected the proposals to use it as an anti-tank cannon not because they believed their 47/32 was good enough, or that they saw no potential but rather, the awkward to use early armor piercing shell (two piece ammunition) that required a charge table to use in addition to the rather limited capabilities of the 75/18 carriage it was mounted on... though, it was later adopted in 1939 with the single piece armor piercing shell. This might not be such a limiting factor as it was in its field gun configuration as the gun elevation will be the most important factor and not the charge, so it might end up initially (pre production vehicles?) with an IS-2 type situation.

I did take into consideration why they might go for a long 75 and not their anti tank 47 and the reason is simple, the 47/32 (their anti tank cannon) and its later longer version 47/40 is not able to frontally penetrate the Souma S35 at 1 kilometer, barely at 500 meters. Which would be one of the requirements and the 75/34 fits them. (Though you should note that the 75/34 is no 75 mm KwK 40, 6 Pounder and 76 ZiS 3, it is closer in performance to the 50 mm L60 than any of the longer 75-76 1942-43 cannons.

 

[tomo pauk]

I did take into consideration why they might go for a long 75 and not their anti tank 47 and the reason is simple, the 47/32 (their anti tank cannon) and its later longer version 47/40 is not able to frontally penetrate the Souma S35 at 1 kilometer, barely at 500 meters. Which would be one of the requirements and the 75/34 fits them. (Though you should note that the 75/34 is no 75 mm KwK 40, 6 Pounder and 76 ZiS 3, it is closer in performance to the 50 mm L60 than any of the longer 75-76 1942-43 cannons.

Let's not short sell the 75/34 (or the 75/32) - it was not that bad when compared with the Soviet 76.2mm guns or the French/US/Polish 75mm (granted, it was under-powered when compared with the KwK 40). It seems to me that Italians never issued a better AP shot than it was the full-calibre and full-weight, 'plain' AP, meaning that acually killing a Sherman, Valentine or Matilda will depend a lot on the luck and courage of the crews, as well as the abilities of the cannon.
OTOH, it is not a stretch for the gun to receive a better ammo further down the road.

Compared with the 6 pdr - there was no 6pdr in service before well into 1942, making the 75/32 better since it was actually there.

 

[Nell_Lucifer]

Let's not short sell the 75/34 (or the 75/32) - it was not that bad when compared with the Soviet 76.2mm guns or the French/US/Polish 75mm (granted, it was under-powered when compared with the KwK 40). It seems to me that Italians never issued a better AP shot than it was the full-calibre and full-weight, 'plain' AP, meaning that acually killing a Sherman, Valentine or Matilda will depend a lot on the luck and courage of the crews, as well as the abilities of the cannon.
OTOH, it is not a stretch for the gun to receive a better ammo further down the road.

Compared with the 6 pdr - there was no 6pdr in service before well into 1942, making the 75/32 better since it was actually there.

I mean, it wasn't a bad gun per say... and you are right that it was comparable to other guns at the time... but it was still a field artillery gun if anti-tank capable, being able to use the same ammo as the 75/18 (and I think the 75/27?) which kinda limited how much you could get out of the cannon, the 75/32 had a maximum V0 of 627 m/s while the 75/34 of 637 m/s, comparable with the Soviet guns at the time. (I believe the 75/34 used both APHE and APBC and later HEAT based on the German shell)

The Italian High Command also recognized the gun when it was adopted (1939) as being an interim anti-tank gun, the 75/46 being a much better choice as it had a higher muzzle velocity though it was twice the weight of the 75/32. So, I guess the gun is a solid choice until 1941 when the Italians start fighting against the Matilda II and later against the T-34 (as OTL it was unable to penetrate the frontal upper plate of a T-34 at close as 300 meters)

(I believe they could increase the performance of the ammo even if they are limited by the case length - 301 mm I think - by changing the propellant to higher pressure ones like the Romanians did with the Resita M1943 but it would wear the barrel at quite the fast rate)

 

[tomo pauk]

I mean, it wasn't a bad gun per say... and you are right that it was comparable to other guns at the time... but it was still a field artillery gun if anti-tank capable, being able to use the same ammo as the 75/18 (and I think the 75/27?) which kinda limited how much you could get out of the cannon, the 75/32 had a maximum V0 of 627 m/s while the 75/34 of 637 m/s, comparable with the Soviet guns at the time. (I believe the 75/34 used both APHE and APBC and later HEAT based on the German shell)

The well-protected tanks will not be defeated by the APHE. The APCBC will work, but it is still the low MV shot (it worked well with the very powerful guns like the 77mm HV or the 17pdr). The APCR (a.k.a PzGr 40 in German parlance, or the HVAP in US parlance), let alone the APDS will provide much greater MV, and with it the increase of armor penetration.
Yes, I'm pushing it a bit with APDS for the Italians here.

The Italian High Command also recognized the gun when it was adopted (1939) as being an interim anti-tank gun, the 75/46 being a much better choice as it had a higher muzzle velocity though it was twice the weight of the 75/32. So, I guess the gun is a solid choice until 1941 when the Italians start fighting against the Matilda II and later against the T-34 (as OTL it was unable to penetrate the frontal upper plate of a T-34 at close as 300 meters)

The much greater weight of the 75/46 was a product of the gun having the heavy AA carriage. The 75/46 ordnance mated to the carriage or the 100/102/105mm howitzer will work well for the Italians. Again, it will work even better with the better ammo.

(I believe they could increase the performance of the ammo even if they are limited by the case length - 301 mm I think - by changing the propellant to higher pressure ones like the Romanians did with the Resita M1943 but it would wear the barrel at quite the fast rate)

Note the cartridge size for the Resita gun - 561mm length. Does not paint the whole picture, but we're looking at the Romanian equivalent of the 17pdr muzzle-energy-wise if the Wikipedia data is to be believed.

added: seems like the 4.1 kg shot (same as on the pak 40?) was fired at 1030 m/s, ie. not quite the 17pdr performance; still good enough for such a light and simple gun.

@mack8 - care to inform us more about the Resita gun?

 

[Nell_Lucifer]

Note the cartridge size for the Resita gun - 561mm length. Does not paint the whole picture, but we're looking at the Romanian equivalent of the 17pdr muzzle-energy-wise if the Wikipedia data is to be believed.

added: seems like the 4.1 kg shot (same as on the pak 40?) was fired at 1030 m/s, ie. not quite the 17pdr performance; still good enough for such a light and simple gun.

@mack8 - care to inform us more about the Resita gun?

This guy on deviantart did a bunch of research on the gun and its ammunition, got his hands also on the training manual from 1943.

 

[Garrison]

If put under Rommel's command, they could make a difference in North Africa, although I doubt it'd be enough to get Rommel to the Nile.

Given Italian production issues I doubt where it would come to more than a couple of dozen tanks and that's assuming they weren't lost during Operation Compass. The Italian problems in the war are systemic, low levels of industrialization, poor productivity, shortages of resources and a military leadership that had been thoroughly politicized, a few better tanks are not going to fix any of that.