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The M4A1(76M1), Experimental 76mm Gun Tank


The M4A1(76M1), Experimental 76mm Gun Tank   

58 members have voted

  1. 1. Would you like to see this vehicle in the game?

    • Yes
      56
    • No
      2
  2. 2. What BR Range should it have?

    • 3.7
      6
    • 4.0
      14
    • 4.3
      36
    • I voted "No" in the first question.
      2
  3. 3. What part of the Tree should it be in?

    • Premium (GE)
      15
    • Premium (Pack)
      9
    • Premium Gift/Event
      16
    • Regular Tree (explain reasoning)
      16
    • I voted "No" in the first question.
      2


I would like to suggest the addition of the M4A1(76M1) Experimental 76mm Gun tank.  Also known as the Quick Fix 76mm Sherman.  Since only 12 of these were produced, it would make sense for it to be some form of premium vehicle.  Ideally, either a purchasable/pack premium or a Limited time Gift/Event vehicle.  

 

This vehicle represents America's first foray into trying to up gun the M4 Sherman Medium Tank

 

This text is quoted from R.P. Hunnicutt's "Sherman, A history of the American Medium Tank".  Pages 198-202

Spoiler

OCM Item 17202 of 11 September 1941 outlined the military characteristics of the M4 Tank.  It included the provision for interchangeable turret face plates which could be used to mount a variety of Armament.  The proposals for the improved Shermans showed the 105mm howitzer and the 3 inch gun as alternates to the 75mm gun M3.  The 3 inch gun M7 had better armor piercing performance and was already standardized as the main armament of the heavy tank M6.  However, it was considered too heavy for installation in the medium tank turret.  A weapon was needed which would have the armor penetration of the 3 inch gun, but could replace the 75 in the standard M34 mount.  To achieve this objective, a development program began for a new gun designated as the 76mm gun  T1. 

    

Although referred to as a 76mm gun, the experimental cannon actually had a 76.2mm or 3 inch bore.  To shorten the development cycle, the projectiles for the 3inch gun M7 were adopted for the new weapon.  The powder charge in a smaller diameter cartridge case was adjusted to obtain the same 2600ft/sec muzzle velocity as the 3 inch gun.  The barrel was lighter in weight than the 3 inch tube and, as originally designed, had a bore length of 57 calibers.  Fitted with the same breech ring assembly as the 75mm gun M3, the new weapon could be installed in the standard combination gun mount M34. 

 

Two 76mm guns T1 were manufactured and shipped to Aberdeen Proving Ground for tests starting on 1 August 1942.  One gun was fired on a fixed test mount and the other was installed in the turret of an M4A1 (registration number W-3060572).  In the M34 Tank mount the long barreled cannon was badly unbalanced.  This was partially corrected by cutting 15 inches from the muzzle end of the tube and adding weight to the breech ring.  After completion of the firing tests, Aberdeen concluded that the 76mm gun T1 was satisfactory for use in the M4 Medium tank series with the modifications specified. 

 

Based on the early test results, the Ordnance Committee on 17 August 1942 recommended that the M4 Armed with the 76mm gun be classified as Substitute Standard.  The T1 gun also was standardized as the 76mm gun M1 and this was added in parentheses to the tank's designation when it was armed with this weapon.  For example, an M4A1 armed with a 76 became the medium tank M4A1 (76M1).  At this time, it was planned to modify production orders to provide for the manufacture of 1000 76mm gun tanks. 

 

The testing program continued at Aberdeen with a production 76mm gun M1, now installed in medium tank M4A1, serial number 549.  This tank, registration number W-3015305, carried the weapon in the newer combination gun mount M34A1 equipped with a direct sight telescope.  Elevation for the 76 in this mount ranged from +25 to -12 and 1/2 degrees.  A number of minor changes were also introduced.   These included the use of a new turret front plate and spacer which moved the gun forward 2 inches.  This provided more room behind the gun preventing interference between the recoil guard and the radio.  The gun was balanced by adding weights to the recoil guard.  This was necessary to permit proper operation of the gyro-stabilizer.  Stowage space was provided for 83 rounds of 76mm ammunition. 

 

Like the earlier part of the program, these tests indicated that the 76 could be satisfactorily installed in the M4.  They also showed that much greater accuracy was possible using the M51(T60) 3-power direct sight telescope over the earlier periscopic sight.  However, the turret itself was badly out of balanced when fitted with the long barreled cannon.  On a 30 percent slope, it was extremely difficult to traverse, although both the Westinghouse and Oilgear systems succeeded in doing so.  An 800 pound counterweight at the rear of the turret was recommended as a cure for the unbalance and it was suggested that the weight be added as a stowage box.  Once balanced, any of the standard drive mechanisms could easily traverse the turret.

 

Twelve medium tanks M4A1(76M1) were produced at Pressed Steel Car Company for evaluation at Aberdeen, the Armored Force Board, and the Tank Destroyer Board.  On 2 February 1943, one of these tanks, registration number W-3015954, arrived at Fort Knox followed later that month by number W-3016065.  These tanks incorporated many of the modifications recommended by Aberdeen including the counterweight added as a turret bustle.  Gun traveling locks had been installed both on the front plate and the rear deck allowing the weapon to be locked in either position.  Service tests began immediately and continued on a 24 hour basis with the final report being submitted on 5 April 1943. 

 

The Armored Force did not agree with the earlier test results.  They concluded that the turret arrangement was unsatisfactory mainly because of inadequate space.  They pointed out that the tank represented a "quick fix" design that was improvised from available components in order to achieve rapid production.  This was, of course, true and it reflected the original intention to produce large numbers of 76mm gun tanks prior to 31 December 1942.  After the rejection of the vehicle by the Armored Force, the Ordnance Committee revoked the Substitute Standard classification and cancelled the production of 17 additional tanks which had been authorized to equip a complete company.  They also recommended that Aberdeen Proving Ground, the Armored Board, and the Tank Destroyer Board each retain one of the 12 tanks already manufactured.  The remaining nine were to be rebuilt as standard 75mm gun vehicles. 

 

Scans of the Relevant pages:

Spoiler

image.thumb.png.8239089cf5f8e6b5a13d9733image.thumb.png.c8db4098171dd3e8266ec4f2

image.thumb.png.c4e5e1ce4ebc34198f04b6d5image.thumb.png.6c755f0f72be6911a4528309

image.thumb.png.8e8a4b6ef78b0a826c843317image.thumb.png.47ecf96a89b94231a13235a7

image.thumb.png.a33db89c07eff170b95057a9

 

 

As a Secondary source, here are some pages from "M4(76mm) Sherman Medium Tank 1943-65", By Steven Zaloga

Spoiler

image.thumb.png.0d8d9581ac2069d88de98e07image.thumb.png.0ca867036ea70e06081e4275

image.thumb.png.47ed6fd9df52f569f3e7dd91image.thumb.png.b442d5a3eb6f211de5aafc51

 

 

There are some Key Issues with information on this vehicle.  Hunnicutt's Sherman does Not provide a Data sheet for this vehicle.  And neither book shows a layout of the ammunition stowage.  Though, it is assumed, that it uses the standard layout used with the 75mm ammunition, in essence, 3 sponson racks, with the rest in turret ready racks or below the turret basket floor.  Also, neither of the books that I have, list the combat weight of the vehicle.  

 

As far as Armor is concerned, the 12 produced vehicles, used standard mid production M4A1 Hulls, which are already modeled in game on the 75mm M4A1.  They used the standard Mid Production low bustle 75mm turret, with the M34A1 Gun mount and shield, which again is already modeled in game on the later 75mm Shermans.  And, they used the mid production cast single piece transmission/final drive housing which is 50.8mm on the front parts, this again is already modeled in game on the M4 Sherman 75.

 

As time permits, I will continue to add more data about this tank as I find it.  I'm still looking for archival data that mentions the ammo layout, rate of fire, combat weight, etc.

 

And to finish off.  More Archival pictures of the actual vehicle from Aberdeen proving grounds.

Spoiler

m4a1_psc51.JPG

m4a1_psc47.JPG

m4a1_psc49.JPG

m4a1_psc50.JPG

 

 

 

Book References:

R.P. Hunnicutt's "Sherman, A History of the American Medium Tank"

"M4(76mm) Sherman Medium Tank 1943-65", By Steven J. Zaloga

 

Web Reference, where the pictures at the end are from

http://the.shadock.free.fr/sherman_minutia/manufacturer/m4a1psc/m4a1_psc.html

Edited by SAUBER_KH7
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Thanks :salute:

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+1, I put pack because there is not as many packs at that tier.

 

I put 4.0, but there wasn’t a number easy to find for the penetration.  I went off of the 116mm at 500m for the other source listed: 4.0 because compared to the Panzer IV G for reference, it would have slightly better armour (angled 50.8mm CAS vs 80mm flat RHA, but weaker turret), slightly more mobility if like the M4A1 (76) W, but a weaker gun by ~20mm of penetration.

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+1

4.0

I've always consider that the M4A1(76)W should be 4.3 and the M4A2(76)W 4.7 but after the New Penetration Formula (I'm still againts it btw) I guess they are ok. The thing is, at 4.0 to 4.3 the U.S. tree lacks any kind of vehicle and I think this one would fit very comfy in there.

 

ps. Calliope is just a gimmick tbh.

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  • 6 months later...

I voted 4.3 (where 75mm M4A2 used to be) and regular tree. It has the worse-angled early hull and slightly worse turret, compared to M4A1(76)W, so would do well in the game as a transitional model between the 75mm Shermans and the first full-production 76mm.
 

My reasoning is that, as you say on your suggestion, the M4A1(76M1) was originally declared substitute standard and planned for production in enough numbers to equip a full company, as part of 1942 plans to produce large numbers of 76mm Shermans. While the AGF may have had some fair reasons for rejecting this particular version of the 76mm Sherman, they were inherently biased against upgunning the Sherman and would drag their heels on the 76mm upgrade for years, costing many lives in the meantime when Shermans started encountering Panthers in much greater numbers than anticipated.
 

While these tanks never saw service, they easily could have (and arguably should have) been sent to the front to be field tested by a company, as seems to have been the original intention. We also have the prototype M6A1 in the tree already, which was planned to serve as a Lend-Lease tank for Britain but ultimately never left the US, where it served as a training tank. Considering that, I feel it’s appropriate to have the M4A1(76M1) in the tree as well, since this is also a vehicle that could have seen combat if things had gone differently, and which (arguably unlike M6A1) would fill a necessary role in the tech tree.

 

A better premium choice would, I think, be the original one-off test bed M4A1 with the longer L/57 T1 gun whose test results led to the changes implemented in the M4A1(76M1). With poor gun handling but higher velocity (and therefore penetration) it could provide a Firefly-style tank destroyer option for those willing to pay or grind for it in an event, and the AP alone might force a higher BR, so it’s unlikely to be able to fill the 4.3 medium tank gap the US tree currently has, unlike M4A1(76M1), which is ideal.

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  • 2 weeks later...

personally i am asupporter for more nations to get "foldered" variants on the same Rank and not only the Soviets with their T-34's and KV-1s, i wouldn't go as far as say I dream about the many Shermans, Lees and Stuarts they could add, but whenever we get a new update it really brings back those "feels", additionally this prototype would fit perfectly at the BR4.0~4.3 gap because there's nothing there besides the premium T14

 

On 19/10/2019 at 17:55, Zombificus said:

A better premium choice would, I think, be the original one-off test bed M4A1 with the longer L/57 T1 gun whose test results led to the changes implemented in the M4A1(76M1). With poor gun handling but higher velocity (and therefore penetration) it could provide a Firefly-style tank destroyer option for those willing to pay or grind for it in an event, and the AP alone might force a higher BR, so it’s unlikely to be able to fill the 4.3 medium tank gap the US tree currently has, unlike M4A1(76M1), which is ideal.

 

there's room for all of them because all 3 "phases" of the program had subtle differences

"phase I": a standard M4A1 with the T1 gun that was effectively non-stabilized, at BR3.7~4.0 as the M4A1 (T1)

"phase II": solved the issues with the unbalanced gun and was now standardized as 76mm M1, additionally it received a wider gun shield, at BR4.0~4.3 as the M4A1#549 (76M1) or M4A1 (76M1) #549 (chassis number of one of the prototypes)

"phase II": old style 75mm turret (large hatch turret) with a enlarged turret bustle to counter the weight of the cannon, at BR4.3 as the M4A1 (76M1)

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I think this would be better in the regular tree, there are already 2 premiums at 4.3 (Calliope and T14) and this would do well in a lineup with the M4A2 and one or more of the existing premiums. 

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1 hour ago, SuperCookie78 said:

My only question which mantlet would you choose. it is pictured having both the skinny m34 or the wider m34a1. the latter offers better protection. also here is great website for sherman research. http://the.shadock.free.fr/sherman_minutia/index.html I used it for both my m4a1 (751St) and M4A1 Micheal. 

 

I think it should probably be the M34A1. Some of the pictures (the ones with the long gun) are of the very first prototype, which had a bunch of flaws that were fixed when they made the 76M1. One of the changes made was to swap to the M34A1 mantlet because the basic M34 was, as well as being somewhat less protective, not quite cutting it for mounting the 76mm. The main solution to the first prototype's poor gun handling was to reduce the barrel length on future prototypes, but the whole M34A1 mounting system did a better job dealing with the weight of the new gun, so they made the change to that as well. It's possible some of the 76M1s had the M34 mantlet, but it wasn't the intention to produce them that way and if the 76M1 had gone to production, it would definitely have been with the M34A1.

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2 hours ago, SuperCookie78 said:

My only question which mantlet would you choose. it is pictured having both the skinny m34 or the wider m34a1. the latter offers better protection. also here is great website for sherman research. http://the.shadock.free.fr/sherman_minutia/index.html I used it for both my m4a1 (751St) and M4A1 Micheal. 

 

if you are choosing which is the best then it is obviously the 2nd pilot (M4A1 #549) and the 12 "pre-production" M4A1(76M1) with the M34A1 gun mount, but even between them the "pre-production" ones were better, or should I say more complete or more standard

if you are thinking which fits the game/BR gap the best it's all 3 versions because the 1st pilot is clearly inferior and can fit BR4.0 (depending on some factors even 3.7) and the other 2 versions fit BR4.3 like a glove (only without HVAP/APCR), either way they would look great in a folder at 4.0~4.3 after the M4A2 and before the M4A1 (76) W, they could even take the 2nd pilot (number 549) and make it a premium

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  • 8 months later...
10 hours ago, Jarms said:

With all the 76 Sherman’s moving up this might as well be the new 4.7. 

 

sure for the pre-production "prototypes" that had most issues solved, but the earlier prototypes would have quite a few limitations and are only suitable for 4.0 to 4.3

in reality the 76mm Shermans are overtiered, there's no way a M4A3 (76)W is as good as a Panther and stronger than a IS-1 (5.3), neither is the Jumbo 76 (6.0) better than a IS-2 (5.7)

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