Sir John Valentine Carden Survives. Part 2.

[allanpcameron]

So I've managed to read all the posts, and enjoyed the discussion, some of you just love the gun debates. All the sources I have looked at aren't terribly helpful about the genesis of the 77mm HV, hence my convoluted use of the 75mm HV based on a Vickers interwar 75mm AA gun. As to the next phase and gun, well you'll just have to wait and see. (In other words I'm hoping that your discussions about it will give me the idea of where to go next specifically.)
I watched an episode of the Star Trek Strange New Worlds which had James T Kirk noting that he didn't know that poutine came with gravy. I thought of you guys.
Allan.

 

[MattII]

So I've managed to read all the posts, and enjoyed the discussion, some of you just love the gun debates. All the sources I have looked at aren't terribly helpful about the genesis of the 77mm HV, hence my convoluted use of the 75mm HV based on a Vickers interwar 75mm AA gun. As to the next phase and gun, well you'll just have to wait and see. (In other words I'm hoping that your discussions about it will give me the idea of where to go next specifically.)

That was my assumption of how it started too. I mean, most of the other guns in production in Britain were 3-inch/76.2mm in bore, so specifically 75mm narrowed it down a bit, especially once I learned that Vickers themselves were making it.

 

[misterwibble]

LOL, I have seen his photo on the net of him being procesed as POW. I always wonderd what the GI that accepted his surrender must have thought.. (What the F**k, Japs...). It would have been even an greater story if the US army also "conscripted"him to act as an Intrepeter in the Pacific. Imagening the story of "Going around the World in Four Armies....

The expression on his face does suggest "Shit, here we go again."
He actually settled and lived the rest of his life in the US. Possibly because they were the first country that didn't conscript him.

 

[ArtosStark]

That was my assumption of how it started too. I mean, most of the other guns in production in Britain were 3-inch/76.2mm in bore, so specifically 75mm narrowed it down a bit, especially once I learned that Vickers themselves were making it.

Kind of treading over ground already covered here by myself and others, but I am pretty sure the OTL 75 mm AA gun from the 30’s had basically nothing to do with the HV 75 mm. As mentioned I am pretty sure the AA gun stopped production in 1939 at latest. And the HV 75 mm was effectively made for a 3” 20 cwt shell necked down for American 75 mm projectiles. It’s possible that prior, limited experience with the 75 mm AA made Vickers more amenable to the cartridge. It’s also possible that some production equipment for 75 mm survived which made Vickers confident that a 75 mm tank gun would ensure they were the ones getting the orders. With plans for the QF 75 mm to take a greater role there may have been incentive for Vickers to add tank ammunition to a calibre that they thought they could provide better than their competitors.

I don’t know. This is just speculation. But it is the most I can see the OTL 75 mm AA gun affecting the design of the HV 75 mm. As it was, I think the British had the right idea switching out the American projectile for that of the 17 pounder to make the 77 mm.

 

[Derek Pullem]

Kind of treading over ground already covered here by myself and others, but I am pretty sure the OTL 75 mm AA gun from the 30’s had basically nothing to do with the HV 75 mm. As mentioned I am pretty sure the AA gun stopped production in 1949 at latest. And the HV 75 mm was effectively made for a 3” 20 cwt shell necked down for American 75 mm projectiles. It’s possible that prior, limited experience with the 75 mm AA made Vickers more amenable to the cartridge. It’s also possible that some production equipment for 75 mm survived which made Vickers confident that a 75 mm tank gun would ensure they were the ones getting the orders. With plans for the QF 75 mm to take a greater role there may have been incentive for Vickers to add tank ammunition to a calibre that they thought they could provide better than their competitors.

I don’t know. This is just speculation. But it is the most I can see the OTL 75 mm AA gun affecting the design of the HV 75 mm. As it was, I think the British had the right idea switching out the American projectile for that of the 17 pounder to make the 77 mm.

So I've managed to read all the posts, and enjoyed the discussion, some of you just love the gun debates. All the sources I have looked at aren't terribly helpful about the genesis of the 77mm HV, hence my convoluted use of the 75mm HV based on a Vickers interwar 75mm AA gun. As to the next phase and gun, well you'll just have to wait and see. (In other words I'm hoping that your discussions about it will give me the idea of where to go next specifically.)
I watched an episode of the Star Trek Strange New Worlds which had James T Kirk noting that he didn't know that poutine came with gravy. I thought of you guys.
Allan.

Don't know about others but I'm going with the author on this one

 

[ArtosStark]

As to the next phase and gun, well you'll just have to wait and see. (In other words I'm hoping that your discussions about it will give me the idea of where to go next specifically.)

A development of the 3.7” AA gun seems like the best next step to me. IOTL it was apparently the basis for the TOG II’s 28 pounder gun, which apparently had similar performance to the 17 pounder but with more HE at the cost of less ammo and more difficulty in loading. Later the 3.7” (94 mm) was used to develop the 32 pounder (originally 37 pounder but the 32 pound projectile was found to be better). So that, or and earlier 20 pounder (84 mm) seem like good options. I suppose it depends on the requirements for penetration, ammo capacity and size of tank and turret ring.

 

[ArtosStark]

Don't know about others but I'm going with the author on this one

Different worlds. I am talking about the OTL development. Allen used something a little different for TTL. And that’s fine by me. But the actual context does matter if we are figuring out how it will perform, if nothing else.

 

[Derek Pullem]

A development of the 3.7” AA gun seems like the best next step to me. IOTL it was apparently the basis for the TOG II’s 28 pounder gun, which apparently had similar performance to the 17 pounder but with more HE at the cost of less ammo and more difficulty in loading. Later the 3.7” (94 mm) was used to develop the 32 pounder (originally 37 pounder but the 32 pound projectile was found to be better). So that, or and earlier 20 pounder (84 mm) seem like good options. I suppose it depends on the requirements for penetration, ammo capacity and size of tank and turret ring.

I'm wondering if the Tiger II and other super-heavy tanks will mean that the tank version of 3.7" evolves into something akin to OTL 105mm L7 before it is deployed. The barrel looks like its based on a 4" gun so maybe we get a L6.5 102mm as a transition . IOTL there was not time to develop a new gun with wartime urgency - ITTL there just might

 

[kelgar04]

I'm wondering if the Tiger II and other super-heavy tanks will mean that the tank version of 3.7" evolves into something akin to OTL 105mm L7 before it is deployed. The barrel looks like its based on a 4" gun so maybe we get a L6.5 102mm as a transition . IOTL there was not time to develop a new gun with wartime urgency - ITTL there just might

I think it will depend on what happens out East for the Germans right now they are probably encountering war build T-34s by and large which are pretty poor by and large along with some of the Russians heavier tanks as well as export Valiants they will be basing what they build around how to counter these and the follow on models and since they probably don't have any intel on the Big Lads that Sir John is about to roll out they will more than likely be working around countering Soviet Steel.

 

[MattII]

I'm wondering if the Tiger II and other super-heavy tanks will mean that the tank version of 3.7" evolves into something akin to OTL 105mm L7 before it is deployed. The barrel looks like its based on a 4" gun so maybe we get a L6.5 102mm as a transition . IOTL there was not time to develop a new gun with wartime urgency - ITTL there just might

Well 3.7" is 95mm, which outdoes the 88mm on the Tigers.

I think it will depend on what happens out East for the Germans right now they are probably encountering war build T-34s by and large which are pretty poor by and large along with some of the Russians heavier tanks as well as export Valiants they will be basing what they build around how to counter these and the follow on models and since they probably don't have any intel on the Big Lads that Sir John is about to roll out they will more than likely be working around countering Soviet Steel.

They'll probably encounter them in Italy. I can only imagine the swearing in the Germany headquarters when they realise the British have an all new tank that rips the hell out of the Panzers.

 

[RCAF Brat]

Well 3.7" is 95mm, which outdoes the 88mm on the Tigers.


They'll probably encounter them in Italy. I can only imagine the swearing in the Germany headquarters when they realise the British have an all new tank that rips the hell out of the Panzers.

It will probably be a similar reaction to their learning that, at combat ranges, an 88mm... ...just bounces off.

 

[MattII]

It will probably be a similar reaction to their learning that, at combat ranges, an 88mm... ...just bounces off.

Yeah, an awful lot of swearing. Also, the fact that the Victor is a 'medium' rather than 'heavy' tank will panic them even more, which will likely mean that the Panther is even more rushed and unreliable.

 

[diestormlie]

Yeah, an awful lot of swearing. Also, the fact that the Victor is a 'medium' rather than 'heavy' tank will panic them even more, which will likely mean that the Panther is even more rushed and unreliable.

"Clearly, the British are producing a Heavy Tank to complement it!"

 

[MattII]

"Clearly, the British are producing a Heavy Tank to complement it!"

The 'heavy tank' is the Venom, which, surprise surprise, will turn out to be the new 'medium'/universal tank.

 

[Paul_Sussex]

So I've managed to read all the posts, and enjoyed the discussion, some of you just love the gun debates. All the sources I have looked at aren't terribly helpful about the genesis of the 77mm HV, hence my convoluted use of the 75mm HV based on a Vickers interwar 75mm AA gun...

I recently came across this post by Tony Williams from 2012 - https://www.tanknet.org/index.php?/topic/35631-vickers-75mm-l50-high-velocity-tank-gun-of-ww2/

Possibly most relevant: "The original 75mm HV used the cartridge case of the 3 inch 20 cwt AA gun (developed in WW1, still in British service in WW2), necked down from 76.2mm to 75mm. The cartridge was intended to use US 75mm tank gun projectiles...The only difference between the 75mm HV and the production 77mm was the fractional difference in calibre: the 77mm cartridge case was therefore exactly the same as that for the 3 inch 20 cwt, although the projectiles were different and it was loaded to a much higher performance..." and "It is not clear why Vickers decided to neck down the 3 inch 20 cwt case to take the US 75mm projectiles, before restoring it to the original 76.2mm calibre. 75mm was not a standard British calibre, whereas 76.2mm certainly was and had already been selected as the calibre for the 17pdr gun early in 1941, a year before the 75mm HV was proposed and several months before the US M3 tank (the first with a 75mm gun) entered service with the British Army..."

 

[Bougnas]

A 6 pdr case necked out to use 17 pdr projectiles and fired from a 6pdr gun with suitably modified barrel instead of the OQF 75mm would have been quite a sight to see, although I'm not certain the Churchill, Valentine and Cromwell could then use the slightly longer ammo and possibly heavier barrel relative to the OTL 75. Still, better projectile than US APC coupled to a bigger propellant capacity than the 75mm case would have been interesting. The 12 pounder* gun might be evidence this was doable since it was already up to 69mm caliber and a 12 pound projectile with supposedly a 6 pdr case.

*the tank gun offered by Vickers, not the AA gun.​

 

[MattII]

I recently came across this post by Tony Williams from 2012 - https://www.tanknet.org/index.php?/topic/35631-vickers-75mm-l50-high-velocity-tank-gun-of-ww2/

Possibly most relevant: "The original 75mm HV used the cartridge case of the 3 inch 20 cwt AA gun (developed in WW1, still in British service in WW2), necked down from 76.2mm to 75mm. The cartridge was intended to use US 75mm tank gun projectiles...The only difference between the 75mm HV and the production 77mm was the fractional difference in calibre: the 77mm cartridge case was therefore exactly the same as that for the 3 inch 20 cwt, although the projectiles were different and it was loaded to a much higher performance..." and "It is not clear why Vickers decided to neck down the 3 inch 20 cwt case to take the US 75mm projectiles, before restoring it to the original 76.2mm calibre. 75mm was not a standard British calibre, whereas 76.2mm certainly was and had already been selected as the calibre for the 17pdr gun early in 1941, a year before the 75mm HV was proposed and several months before the US M3 tank (the first with a 75mm gun) entered service with the British Army..."

Well however it comes to be, using the American shells means the Victor will have HE available from the start.

 

[Salamander]

Vickers could always use this as the basis of their 3" tank gun. After all, they were already making them.

Vickers Model 1931 - Wikipedia

en.wikipedia.org

 

[MattII]

Vickers could always use this as the basis of their 3" tank gun. After all, they were already making them.

Vickers Model 1931 - Wikipedia

en.wikipedia.org

I believe they're using the same manufacturing equipment to produce the 75mm HV.

 

[ArtosStark]

Well however it comes to be, using the American shells means the Victor will have HE available from the start.

It would regardless. The 17 pounder had an HE shell as well.

And since we are talking about it taking on Tigers, it should be noted that the US 75 mm AP had issues with penetration and shatter gap (ie, being able to penetrate a target at 1000 yards, or 100 yards, but not in between due to the shell shattering on impact). In 1943 the ordinance board discussed the HV 75mm. Based on their tests the penetration of the HV 75 mm the with US projectile was only 87 mm at 1000 yards and 30 degrees. This is about the same as the US 76 mm (which the US Army was disappointed with) and considerably less than the 108 mm the 77 mm achieved with the same case and 17 pounder projectile. For reference, the same tests listed the 6 pounder at 76 mm with APCBC and 106 mm with Littlejohn.

Vickers could always use this as the basis of their 3" tank gun. After all, they were already making them.

Vickers Model 1931 - Wikipedia

en.wikipedia.org

IIRC (and I could have lost track of this) Allen’s HV 75 mm uses the shell from this gun rather than the US shell. Or at least the machinery. That said, most of these guns were built in Romania. Vickers did build some in Britain but as far as I can tell the last were delivered in 1939.

You wouldn’t want to use this one directly in a tank. The shell is long and straight walled, which makes it very awkward to use in a turret and reduces the amount you can carry. I believe the HV 75 mm here uses the projectile (which I don’t know much about) with the shell from the 3” 20 cwt AA gun.