M62 vs M79 availability for the 76mm gun M1

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HypeZephyr
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M62 vs M79 availability for the 76mm gun M1

#1

Post by HypeZephyr » 15 Jan 2022, 00:25

Altho I am aware that M93 HVAP rounds for the 76mm gun M1 were scarce and non existent even in 1944, I would like to know how common would the cheaper solid M79 AP shot be among Sherman tank crews by late 1944.?

And if able, how much percentage of a Sherman tank’s ammunition loadout be made up of M79 ammunition rounds?

Peasant
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Re: M62 vs M79 availability for the 76mm gun M1

#2

Post by Peasant » 15 Jan 2022, 15:24

I second this, I was wondering for quite some time as well.


Richard Anderson
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Re: M62 vs M79 availability for the 76mm gun M1

#3

Post by Richard Anderson » 15 Jan 2022, 18:07

I doubt much, if any 76mm M79 was ever sent to the ETOUSA. All the stock reports refer to either 76mm APC or 76mm M62 APC. The consumption reports do refer to "APC and AP", but without differentiating.
Richard C. Anderson Jr.

American Thunder: U.S. Army Tank Design, Development, and Doctrine in World War II
Cracking Hitler's Atlantic Wall
Hitler's Last Gamble
Artillery Hell

HypeZephyr
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Re: M62 vs M79 availability for the 76mm gun M1

#4

Post by HypeZephyr » 15 Jan 2022, 18:11

Richard Anderson wrote:
15 Jan 2022, 18:07
I doubt much, if any 76mm M79 was ever sent to the ETOUSA. All the stock reports refer to either 76mm APC or 76mm M62 APC. The consumption reports do refer to "APC and AP", but without differentiating.
If we cant find much evidence from stock reports, are there any anecdotal or eye-witness reports of M79 AP ever being used?


Also as a side note: Could you give me a copy of these stock reports? I’d like to see what it says on HVAP and other types of ammunition availability among US tanker crews.

Thoddy
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Re: M62 vs M79 availability for the 76mm gun M1

#5

Post by Thoddy » 16 Jan 2022, 00:10

Was the M79 used in Tunisia?

I suspect if it was used, it was found to be largely ineffective vs Tiger I . The M79 is susceptible to breakage even against moderate thick armour
"Meine Herren, es kann ein siebenjähriger, es kann ein dreißigjähriger Krieg werden – und wehe dem, der zuerst die Lunte in das Pulverfaß schleudert!"

Richard Anderson
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Re: M62 vs M79 availability for the 76mm gun M1

#6

Post by Richard Anderson » 16 Jan 2022, 02:08

HypeZephyr wrote:
15 Jan 2022, 18:11
If we cant find much evidence from stock reports, are there any anecdotal or eye-witness reports of M79 AP ever being used?
Some was apparently used in North Africa and probably Sicily as the 3" for the M10 3" GMC in Tank Destroyer units, but, again, most of the reports lumped them together. You may have some success going through TD and Tank battalion AARs, but typically they do not consistently report such.
Also as a side note: Could you give me a copy of these stock reports? I’d like to see what it says on HVAP and other types of ammunition availability among US tanker crews.
The reports for the ETOUSA and MTOUSA may be found at the Ike Skelton Combined Arms Research Library (CARL) Digital Library as "History of Planning Division, ASF. Volume 9". Otherwise, Fold3 has microfilm copies of the ETOUSA SOS Ordnance Progress Reports (Statistical) and the ETOUSA Ordnance Ammunition History, which has some fragmentary data. The problem, again, is that they did not generally differentiate between the two types of armor piercing projectiles in those reports. The best you can assume is that some M79 was likely used in North Africa and Italy before the more complicated to manufacture M62 became available and replaced it. In the ETOUSA I suspect all initial issues and consumption were M62, until the come to Jesus moment in late June and early July regarding the problems with M62 versus the Panther and following the Ordnance recommendation that M79 might work better (at least that was the hope).
Richard C. Anderson Jr.

American Thunder: U.S. Army Tank Design, Development, and Doctrine in World War II
Cracking Hitler's Atlantic Wall
Hitler's Last Gamble
Artillery Hell

Richard Anderson
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Re: M62 vs M79 availability for the 76mm gun M1

#7

Post by Richard Anderson » 16 Jan 2022, 02:29

I'm afraid the answer is the same for the 76mm, 3", and 90mm HVAP. It was lumped together with AP and APC. As of 14 February 1945, only 4,154 rounds for 3" and 2,348 rounds for 76mm were on hand in ETOUSA depots, with another 7,330 rounds manifested (i.e. somewhere between the US and the depots), and another 16,168 rounds released (i.e. in route from manufacturer to the ports), while another 12,500 were expected released in March. The implication is that by February, about 16,000 rounds of 76mm and about 17,000 rounds of 3" HVAP had been expended.
Richard C. Anderson Jr.

American Thunder: U.S. Army Tank Design, Development, and Doctrine in World War II
Cracking Hitler's Atlantic Wall
Hitler's Last Gamble
Artillery Hell

HypeZephyr
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Re: M62 vs M79 availability for the 76mm gun M1

#8

Post by HypeZephyr » 16 Jan 2022, 09:12

Richard Anderson wrote:
16 Jan 2022, 02:08
HypeZephyr wrote:
15 Jan 2022, 18:11
If we cant find much evidence from stock reports, are there any anecdotal or eye-witness reports of M79 AP ever being used?
Some was apparently used in North Africa and probably Sicily as the 3" for the M10 3" GMC in Tank Destroyer units, but, again, most of the reports lumped them together. You may have some success going through TD and Tank battalion AARs, but typically they do not consistently report such.
Also as a side note: Could you give me a copy of these stock reports? I’d like to see what it says on HVAP and other types of ammunition availability among US tanker crews.
The reports for the ETOUSA and MTOUSA may be found at the Ike Skelton Combined Arms Research Library (CARL) Digital Library as "History of Planning Division, ASF. Volume 9". Otherwise, Fold3 has microfilm copies of the ETOUSA SOS Ordnance Progress Reports (Statistical) and the ETOUSA Ordnance Ammunition History, which has some fragmentary data. The problem, again, is that they did not generally differentiate between the two types of armor piercing projectiles in those reports. The best you can assume is that some M79 was likely used in North Africa and Italy before the more complicated to manufacture M62 became available and replaced it. In the ETOUSA I suspect all initial issues and consumption were M62, until the come to Jesus moment in late June and early July regarding the problems with M62 versus the Panther and following the Ordnance recommendation that M79 might work better (at least that was the hope).

Regarding the Ordinance recommendation against the M79, did this come before or post-insigny? And if its post-indigny, did Ordinance really follow through with their recommendation?

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Re: M62 vs M79 availability for the 76mm gun M1

#9

Post by Richard Anderson » 16 Jan 2022, 09:48

HypeZephyr wrote:
16 Jan 2022, 09:12
Regarding the Ordinance recommendation against the M79, did this come before or post-insigny? And if its post-indigny, did Ordinance really follow through with their recommendation?
Huh? Ordnance did not recommend against M79 before or after the Isigny and other tests. The thought it might work better than M62.
Richard C. Anderson Jr.

American Thunder: U.S. Army Tank Design, Development, and Doctrine in World War II
Cracking Hitler's Atlantic Wall
Hitler's Last Gamble
Artillery Hell

HypeZephyr
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Re: M62 vs M79 availability for the 76mm gun M1

#10

Post by HypeZephyr » 16 Jan 2022, 18:32

Richard Anderson wrote:
16 Jan 2022, 09:48
HypeZephyr wrote:
16 Jan 2022, 09:12
Regarding the Ordinance recommendation against the M79, did this come before or post-insigny? And if its post-indigny, did Ordinance really follow through with their recommendation?
Huh? Ordnance did not recommend against M79 before or after the Isigny and other tests. The thought it might work better than M62.
Oh sorry, that was my bad, I didn't mean to say against.

Regarding this ‘recommendation’ and thought that the M79 would perform against Panthers, did they make it up before or after the Insigny tests? Because if Im aware, Ordnance only really saw the M62 as inadequate after those tests. Beforehand, they were really enthusiastic about replacing the M79 with the M62.

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Re: M62 vs M79 availability for the 76mm gun M1

#11

Post by Richard Anderson » 16 Jan 2022, 19:20

HypeZephyr wrote:
16 Jan 2022, 18:32
Regarding this ‘recommendation’ and thought that the M79 would perform against Panthers, did they make it up before or after the Insigny tests? Because if Im aware, Ordnance only really saw the M62 as inadequate after those tests. Beforehand, they were really enthusiastic about replacing the M79 with the M62.
The initial problems with M62 were found in the ETOUSA in the Shoeburyness tests in May 1944 and were found mostly related to the poor fuze action of the APC design, which was also true in the 75mm and 90mm rounds. So the initial thought was using solid, unfuzed AP shot was a good quick fix. The problems with the APC versus the Panther were first found in the publication of the British analysis of the Panther published 5 June 1944 and then confirmed from early battle experience, leading to the crash program to field 3"/76mm HVAP, which was completed in about five weeks. Then the two Isigny and single Balleroy test further demonstrated the weakness of M62 versus the Panther glacis and the thought again that AP might work better.

"Beforehand", M79 and all other AP shot was authorized Substitute Standard in late 1942 when it was completely replaced in production by APC. Insofar as I can tell, all production of AP shot for the U.S. Army ceased in late 1942 and early 1943 and was only present in ETOUSA/MTOUSA or Z/I depots after that date. Most was probably shot off by mid 1944, but I have never been able to find complete production or expenditure figures that differentiate between the two types. The only production after that was the reheat treated 90mm M77 AP that was designated T33. Postwar though, improved AP designs almost entirely replaced APC.
Richard C. Anderson Jr.

American Thunder: U.S. Army Tank Design, Development, and Doctrine in World War II
Cracking Hitler's Atlantic Wall
Hitler's Last Gamble
Artillery Hell

HypeZephyr
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Re: M62 vs M79 availability for the 76mm gun M1

#12

Post by HypeZephyr » 16 Jan 2022, 23:22

Richard Anderson wrote:
16 Jan 2022, 19:20
HypeZephyr wrote:
16 Jan 2022, 18:32
Regarding this ‘recommendation’ and thought that the M79 would perform against Panthers, did they make it up before or after the Insigny tests? Because if Im aware, Ordnance only really saw the M62 as inadequate after those tests. Beforehand, they were really enthusiastic about replacing the M79 with the M62.
The initial problems with M62 were found in the ETOUSA in the Shoeburyness tests in May 1944 and were found mostly related to the poor fuze action of the APC design, which was also true in the 75mm and 90mm rounds. So the initial thought was using solid, unfuzed AP shot was a good quick fix. The problems with the APC versus the Panther were first found in the publication of the British analysis of the Panther published 5 June 1944 and then confirmed from early battle experience, leading to the crash program to field 3"/76mm HVAP, which was completed in about five weeks. Then the two Isigny and single Balleroy test further demonstrated the weakness of M62 versus the Panther glacis and the thought again that AP might work better.

"Beforehand", M79 and all other AP shot was authorized Substitute Standard in late 1942 when it was completely replaced in production by APC. Insofar as I can tell, all production of AP shot for the U.S. Army ceased in late 1942 and early 1943 and was only present in ETOUSA/MTOUSA or Z/I depots after that date. Most was probably shot off by mid 1944, but I have never been able to find complete production or expenditure figures that differentiate between the two types. The only production after that was the reheat treated 90mm M77 AP that was designated T33. Postwar though, improved AP designs almost entirely replaced APC.
Ahh I see.

Its safe to assume that by 1944, your average tanker would have zero M79 AP rounds available for use, yes?

Richard Anderson
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Re: M62 vs M79 availability for the 76mm gun M1

#13

Post by Richard Anderson » 17 Jan 2022, 00:14

HypeZephyr wrote:
16 Jan 2022, 23:22
Ahh I see.

Its safe to assume that by 1944, your average tanker would have zero M79 AP rounds available for use, yes?
I finally went back to my manuscript to clarify my memory.

3”/76mm: M62 APC was standardized under OCM 16167, between late October 1940 and early May 1941, and was authorized for use in the 76mm Gun M1 under OCM 18656 c. August 1942, M79 AP was approved as substitute standard under OCM 17523 in c. December 1941 and was authorized for use in the 76mm Gun M1 under OCM 19204 of November 1942.

M79 was not actually tested at Shoeburyness or Balleroy, but was tested at 1st Isigny, where the conclusion from the tests was "AP M79 will not penetrate the front slope plate or the mantlet at 200 yards. It holds no advantage over APC M62 ammunition w/BDF M66A1."

Production of significant quantities of 3”/76mm M62 APC and M79 AP did not begin until June 1942. Production of pilot, test, and proof rounds prior to that probably totaled in the 100's. Until then, the main ammunition type available was the 3" HE and Shrapnel round, dating to 1918 and prior.
Richard C. Anderson Jr.

American Thunder: U.S. Army Tank Design, Development, and Doctrine in World War II
Cracking Hitler's Atlantic Wall
Hitler's Last Gamble
Artillery Hell

HypeZephyr
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Re: M62 vs M79 availability for the 76mm gun M1

#14

Post by HypeZephyr » 17 Jan 2022, 06:38

Richard Anderson wrote:
17 Jan 2022, 00:14
HypeZephyr wrote:
16 Jan 2022, 23:22
Ahh I see.

Its safe to assume that by 1944, your average tanker would have zero M79 AP rounds available for use, yes?
I finally went back to my manuscript to clarify my memory.

3”/76mm: M62 APC was standardized under OCM 16167, between late October 1940 and early May 1941, and was authorized for use in the 76mm Gun M1 under OCM 18656 c. August 1942, M79 AP was approved as substitute standard under OCM 17523 in c. December 1941 and was authorized for use in the 76mm Gun M1 under OCM 19204 of November 1942.

M79 was not actually tested at Shoeburyness or Balleroy, but was tested at 1st Isigny, where the conclusion from the tests was "AP M79 will not penetrate the front slope plate or the mantlet at 200 yards. It holds no advantage over APC M62 ammunition w/BDF M66A1."

Production of significant quantities of 3”/76mm M62 APC and M79 AP did not begin until June 1942. Production of pilot, test, and proof rounds prior to that probably totaled in the 100's. Until then, the main ammunition type available was the 3" HE and Shrapnel round, dating to 1918 and prior.
Question 1:
Ahh I see, in that case, the M79 would be available to tanker crews whenever M62 rounds werent available then due to its status as a “substitute” round, yes?


Question 2:
Ive talked to the chieftainWG on reddit (Couldnt find luck on any other website unfortunately) about this same question and he also replied with the same conclusion you made. The only difference is, he stated that US ordnance had a “First in, last out” policy regarding surplus depot ammunition and hence it wasn't impossible for some tanker units to be hurriedly issued M79 so Ordnance could get rid of them. Is this conclusion plausible in your opinion?



Question 3:
As for the Insigny tests, I find it quite odd that the M79 round is considered to “hold no advantages” over the M62. If I recall correctly, almost all sources I could find state that the M79 had a nominally higher penetration advantage over the M62. These sources include Bird and Livingstone, TM 9 1907 (1944 and 1948) and N-4636-C (1944 and 1945) and all of them have stated that M79 AP had a penetration capability of 130mm+ in 200 yards or so, enough to go through the Panther’s mantlet at a centerline angle . If the M62 could penetrate the Panther’s mantlet at 200 yards, so should the M79 theoretically.

However, knowing how little tank rounds were used for the Insigny tests, I assume the reason the M79 failed to perform distinguishably enough is because of the small sample sizes used in the experiment and the rate of error that might have occurred because of it. Rounded angles might have also been a factor into this.

However, this is just my assumption on how the M79 failed. What’s your opinion on this?

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Re: M62 vs M79 availability for the 76mm gun M1

#15

Post by Thoddy » 17 Jan 2022, 16:23

the problem with M79 is the quite large shatter gap.

it has a fairly ok performance at normal attack but shatter against ~0.5 cal plate at around 30-45 degrees obliquity
"Meine Herren, es kann ein siebenjähriger, es kann ein dreißigjähriger Krieg werden – und wehe dem, der zuerst die Lunte in das Pulverfaß schleudert!"

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