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Manic Moran

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Interestingly the KwK 40/L48 was being fielded on the Pzkw IV starting June of 1942, more than two full years before any US forces would have a comparable tank mounted gun. Whatever the reasons, whoever made the decisions, putting a more powerful armor defeating weapon on the M4 fielded by US forces really wasn't taken seriously until the summer 1944.

 

 

Yes, its interesting that a gun developed in late 1939 could be employed in an operational tank two years later. Quite different from a gun developed in summer 1942 being employed in an operational tank two years later. Oh. Wait. Yeah...

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Yes, its interesting that a gun developed in late 1939 could be employed in an operational tank two years later. Quite different from a gun developed in summer 1942 being employed in an operational tank two years later. Oh. Wait. Yeah...

So we're in agreement. Great.

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So we're in agreement. Great.

 

 

 

Oh good. Tinkerbell triumphs again.

 

Except that the M6 heavy was being developed concurrently with the M4 Medium, and 'production' versions had 76mm guns from December 1942.

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Except that the M6 heavy was being developed concurrently with the M4 Medium, and 'production' versions had 76mm guns from December 1942.

 

That and the M18 was sporting the same 76mm in summer 1943 not to mention the M10 production run with the 3" AT gun ran from 1942-1943. Let's not confuse historians with facts. Not when the statement is irrefutable that for whatever reason, for whatever excuse, putting in the field for US tank forces, in combat, an M4 with a comparable weapon to the PkW 40/L48 wasn't a serious concern until the summer of 1944.* It just wasn't.

 

*Some guy named Rich keeps telling us that there were hundreds of M4 tanks with 76mm guns sitting in England unwanted in combat. Guess we ought to introduce him to Rich.

Edited by DKTanker
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So we're in agreement. Great.

 

 

 

Oh good. Tinkerbell triumphs again.

 

Except that the M6 heavy was being developed concurrently with the M4 Medium, and 'production' versions had 76mm guns from December 1942.

 

 

Except? It was the 3" M7 Gun, not the 76mm M1 Gun. Very different beast. With three very indifferent pilots completed by spring 1942.

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That and the M18 was sporting the same 76mm in summer 1943 not to mention the M10 production run with the 3" AT gun ran from 1942-1943. Let's not confuse historians with facts. Not when the statement is irrefutable that for whatever reason, for whatever excuse, putting in the field for US tank forces, in combat, an M4 with a comparable weapon to the PkW 40/L48 wasn't a serious concern until the summer of 1944.* It just wasn't.

 

 

 

*Some guy named Rich keeps telling us that there were hundreds of M4 tanks with 76mm guns sitting in England unwanted in combat. Guess we ought to introduce him to Rich.

 

 

Why is it so hard for you to understand the 3" M7 Gun was not the 76mm M1 Gun?

 

Meanwhile, yes, the M18 began production in July 1943, with all of six completed and 812 completed by the end of the year. AFTER THE 76mm HAD BEEN OFFERED TO THE ARMORED FORCE AND REJECTED, Devers and the Armored Board refused the kludged together turret design. Meanwhile, the M1 76mm Gun was being produced. ASF turned the production over to the M18 GMC. When the redesigned turret from the T23 was completed and accepted by the Armored Board, production of the Medium Tank M4 with 76mm began in January 1944.

 

Why is that so difficult to understand?

 

There were 113 M4A1 76mm (w) in depot in England as of 1 June 1944. Another 40 were unloading or at sea en route to England and arrived during the month, Another 678 (including M4A3) were released and waiting shipment to port of embarkation. Between 18 and 21 July 51 each were assigned to the 2d and 3d AD, with another 50 held in reserve by First Army. The decision not to deploy them before that was made by the Armored Force commanders in England.

 

Not according to "some guy named Rich", but according to NARA RG 492, Records of the ETOUSA AFV&W Section.

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What about putting the 77 mm in British Shermans? Anyone thought of it?

 

They didn't even think of putting the 77mm into the Black Prince, which would have been an obvious candidate,

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Availability might be an issue here. By the time Israel was able to obtain M4s en masse and have things done to them, it was in cooperation with France - so French guns were logical; the 75mm was readily available as the French were toying with it already and same goes for the "step up" to 105mm, so there was little motivation to explore a thing that would bring about as many issues as the 105mm, but with lower performance. At least that would be my take.

Heck, Yugoslavians tried to make a 122mm gun work in Sherman 75 turret as an assault gun :o

 

These were different beast; the French 105mm was a much newer design and was optimized for firing HEAT, no kinetic round available. While the Israelis used the larger turret of the M4(76), the Argentine conversions kept the original turret (many were former Fireflies bought at rock bottom prices after the war) and it worked fine. The WWII vintage 90mm gun was a powerful gun designed to fire high velocity AP rounds. NO hard data on hand, but my guess is this was far heavier and required a more powerful recoil system which would make fitting in on a M4 turret problematic.

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What about putting the 77 mm in British Shermans? Anyone thought of it?

Inertia. So great was the inertia of using the M3 75mm and not up gunning, not even for the available homegrown 76mm and 3", there is no way it could be overcome to install the 77mm.

For US Army yes.

 

But for British it would have produced a more useable tank. The Sherman Firefly is anything but ergonomical to use with the squeezed in 17 pounder.

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About the only thing that could have been (maybe) done was the M4E4 solution used post-war for military aid, putting after all the 76mm gun into Sherman 75 turret - would need Armored Force change of heart though.

On the other hand, it would not make much difference. In the hedgerows of Normandy vs. Panthers, 76mm still has trouble from the front (and so does 17pdr) and 75mm gun is more than enough from the flank. What would have made difference would be HVAP shot, but that is a different story.

 

All in all, at best you'd end up with Firefly-like limited distribution and that is something you got available in real life as well.

 

 

@Gorka L. Martinez-Mezo yeah, I know - the question was "why Israel did not go for the 90mm" and the ties to France (and, in the end, French guns doing same or better job) are probably the main reason. By that time I believe Israel had only the 90mm MECAR gun in stock, and that was a completely different beast and not worth shoehorning to M4 turrets when there were French 75mma nd 105mm guns aplenty.

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What about putting the 77 mm in British Shermans? Anyone thought of it?

 

Same effect if you just refurbish British projectiles for Lend-and-Leased M4/76s.

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US ORDNANCE (not Ordinance)

Thank you.

 

 

You're welcome. I'm afraid constant repetition of this nonsense has forced the tolerance setting on my Stupid-Shitometer to its lowest level and it seems to be stuck there.

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Was there a compelling technical reason why the US couldn't generate more HVAP than it did once the need became apparent?

After all, 4 engine bombers were crossing the Atlantic every day in 1944 (load 'em up with HVAP). It seems that if the need was there and the ammo was being produced that more of it could have been brought to the front.

Unless JCH Lee was involved!

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If I remember correctly, HAVP was incredibly expensive. Also I'm very sure the US tungsten supply was not able to handle anymore then it did. Even today the UK produces more tungsten then the us.

http://investingnews.com/daily/resource-investing/critical-metals-investing/tungsten-investing/top-tungsten-producing-countries-china-russia-canada/

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If I remember correctly, HAVP was incredibly expensive. Also I'm very sure the US tungsten supply was not able to handle anymore then it did. Even today the UK produces more tungsten then the us.

http://investingnews.com/daily/resource-investing/critical-metals-investing/tungsten-investing/top-tungsten-producing-countries-china-russia-canada/

 

Pretty much. It bears understanding too the initial design, testing, production, and operational fielding of HVAP occurred over about six weeks, from early July to the initial field testing at Isigny. Production of the 76mm averaged just over 2,100 rounds per month for the six months of 1944 it was produced and just over 6,000 per month for the eight months of 1945 it was produced. For the 3" it was 2,800 rounds per month for five months in 1944 and 4,750 for four months in 1945. So not a huge production compared to standard M62 AP or British 17-pdr.

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that's not a lot of ammo for an army.

Six weeks is an impressive development cycle but old fashioned tank ammo isn't that hard to make and even HVAP is old fashioned in the scheme of things.

I'm pretty sure that the M62 AP was an okay round at best. The tube and recoil mechanism should've been able to handle a better AP round.

The real problem was that the Allies were constantly on the offensive and suffered more for it. The German guns and armor were less of an issue once the drivetrains and fuel tanks ran out.

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that's not a lot of ammo for an army.

Six weeks is an impressive development cycle but old fashioned tank ammo isn't that hard to make and even HVAP is old fashioned in the scheme of things.

I'm pretty sure that the M62 AP was an okay round at best. The tube and recoil mechanism should've been able to handle a better AP round.

The real problem was that the Allies were constantly on the offensive and suffered more for it. The German guns and armor were less of an issue once the drivetrains and fuel tanks ran out.

 

Yep, it isn't, but there were reasons for it. It was expensive to produce and Ordnance had little priority for tungsten carbide.

 

Yep, M62 was a product of the belief HE was needed for an adequate behind armor effect. However, the cavity weakened the penetrator and the fuzing too often actuated on impact instead of after penetration. AP shot was probably a better choice, but early experience with 75mm AP was poor, so it was decided to stick with M62.

 

It was evident to the Ordnance officers in the field that the 76mm M1 Gun could easily handle a higher chamber pressure and urged increasing the propellant load in the cartridge without avail. The AFV&W Section postwar history is pretty bitter about it and points to overly conservative officers in CONUS wanting to ensure longer barrel life at the expense of lives.

 

Yes, being on the offensive constantly was part of it, but also there simply wasn't much time for a feedback loop to work. HVAP was an exception; improved 76mm and 90mm AP had almost zero effect on the war, because the problem wasn't realized until summer-fall 1944.

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I talked to a WW2 some years ago and he really had a beef with stateside officers and gun tube wear. He said the 75 and the 76 both could've taken way more propellant safely. This was in the mid nineties and he was still mad as hell about it. I think he had talked about the accuracy issues of changing propellant and it was his opinion that the gunsights wouldn't change at all for the difference in feet per second and trajectory if the propellant was increased by 15% or so.

It's been a long time ago now and the specifics escape me but he was sure of himself and seemed to know what he was about

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I talked to a WW2 some years ago and he really had a beef with stateside officers and gun tube wear. He said the 75 and the 76 both could've taken way more propellant safely. This was in the mid nineties and he was still mad as hell about it. I think he had talked about the accuracy issues of changing propellant and it was his opinion that the gunsights wouldn't change at all for the difference in feet per second and trajectory if the propellant was increased by 15% or so.

It's been a long time ago now and the specifics escape me but he was sure of himself and seemed to know what he was about

 

I'm not surprised. Ordnance also resisted using various chemicals to reduce smoke and flash on the grounds they increased wear. The primer in the early 76mm cartridge was also a base ignition tube, which left a lot of the propellant either partially or completely unburned, which led to the early complaints about excessive flash and smoke. At one point Armor was reluctant to accept the 76mm because it was looking like the TC would have to dismount to sense the round! (It may also have factored into the decision against employing the 76mm-armed tanks in England on D-Day.) Luckily, a full-length ignition tube was developed and deployed quickly, becoming common by late fall, which reduced the flash and smoke. Of course, on top of that there was resistance to development of the muzzle brake.

 

All these were REAL faults by Ordnance. There is enough of them that fictitious ones don't need to be created.

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it seems that the biggest fault was testing shell vs. US armor, not vs "german equivalent", leading to the problems with shatter etc.; everything else is secondary - as even if you increase MV with hotter propellant, shell would still suffer. Then again, Brits had the same issues in first half of the war. And APHE worked for Germans throughout the war.

 

In the end it is a lot like with the 88mm gun. Even when the actual AT gunners preferred 50mm and 75mm, still the 88mm had bigger psychological impact both on enemy and own troops (made bigger booms, had cooler caliber...).

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that's not a lot of ammo for an army.

Six weeks is an impressive development cycle but old fashioned tank ammo isn't that hard to make and even HVAP is old fashioned in the scheme of things.

I'm pretty sure that the M62 AP was an okay round at best. The tube and recoil mechanism should've been able to handle a better AP round.

The real problem was that the Allies were constantly on the offensive and suffered more for it. The German guns and armor were less of an issue once the drivetrains and fuel tanks ran out.

 

Yep, it isn't, but there were reasons for it. It was expensive to produce and Ordnance had little priority for tungsten carbide.

 

Yep, M62 was a product of the belief HE was needed for an adequate behind armor effect. However, the cavity weakened the penetrator and the fuzing too often actuated on impact instead of after penetration. AP shot was probably a better choice, but early experience with 75mm AP was poor, so it was decided to stick with M62.

 

It was evident to the Ordnance officers in the field that the 76mm M1 Gun could easily handle a higher chamber pressure and urged increasing the propellant load in the cartridge without avail. The AFV&W Section postwar history is pretty bitter about it and points to overly conservative officers in CONUS wanting to ensure longer barrel life at the expense of lives.

 

Yes, being on the offensive constantly was part of it, but also there simply wasn't much time for a feedback loop to work. HVAP was an exception; improved 76mm and 90mm AP had almost zero effect on the war, because the problem wasn't realized until summer-fall 1944.

 

Same for the 3" they had done tests with the velocity ramped up and the pressure and the gun handled them fine.

Heck the actual case had a distance wad in it, which would have made it easier to add more powder.

 

 

The m62 at 2800 ft/sec wouldn't have been to shabby and I doubt it would have added much extra wear to the guns.

Edited by whelm
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Same for the 3" they had done tests with the velocity ramped up and the pressure and the gun handled them fine.

 

Heck the actual case had a distance wad in it, which would have made it easier to add more powder.

 

 

The m62 at 2800 ft/sec wouldn't have been to shabby and I doubt it would have added much extra wear to the guns.

 

 

Yep they were both typical early 20th century engineering...or over-engineering. The reality is what made the 17-pdr "better" was more propellant generating greater chamber pressure and Mv. Not rocket science.

 

OTOH, I suspect greater Mv in the M62 would have led to more shattering and more premature fuze actuation.

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