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  • Turn up the HEAT.

    It is generally accepted that the Shermans M3/L40 main gun was relatively ineffective firing AP rounds at armour.
    It is also true that the fire control system and optics (Good target acquisition) were actually quite good,even ground breaking in certain aspects. Rudimentary gun stabilization and a very fast initial traverse followed by "fine aiming" being the major refinements.
    It follows that the gun itself was very accurate,being built in massive numbers to very fine tolerances as only the US could in WW2.
    There is nothing but praise for the guns performance in its rate of fire and ability to suppress soft targets.
    This being the case, why was there no effort made to develop a HEAT round for the gun?
    The technology was available (The Munroe effect was fully understood by the early 1940s) and in use in hand held anti armour weapons such as Panzerfaust ,PIAT and Bazooka as well as demolition charges and mines.
    The rule of thumb regarding shaped charge was and still is:
    Penetration = 3-5 x calibre of charge. There are of course many variables but it's a rule of thumb for laymen (me) and not a mathematic formula.
    This would theoretically give the M3/L40 an armour penetration of between say 200-400mm.
    I know that the spin imparted on a HEAT round fired from a rifled barrel adversely affects the penetration but even so............!
    The HEAT round has only slightly less explosive energy than an HE round so if no enemy armour was present (as was often the case) there is no redundant rounds in the tanks loadout.
    Does anyone out there know why such a round was never developed?

  • #2
    Originally posted by flash View Post
    It is generally accepted that the Shermans M3/L40 main gun was relatively ineffective firing AP rounds at armour.
    That isn't true at all. It wasn't a great cat-killer but there were never very many of those around anyway.

    This being the case, why was there no effort made to develop a HEAT round for the gun?

    Does anyone out there know why such a round was never developed?
    The 75mm Pack Howitzer fired the same projectiles and the M3 tank gun, it just used a shorter case and lower propelling charge. A HEAT round was developed and used for this weapon but the armor penetration was quoted as only 3-inches (76.2mm), or in other words hardly an improvement over AP fired from the M3.

    The German's of course also developed 75mm HEAT rounds for the PAK 97/38 which fired essentially the same 75x350R ammunition as the M3. The German's did several generations of development on this and end up with marginally better performance, but only marginal.

    The technology of firing HEAT rounds from rifled guns was during the war just not up to the task of delivering significantly better penetration. I think a HESH round would have been more promising but that would have to wait slightly longer. A HVAP round was developed to the prototype stage for the M3 tank gun and it showed quite a bit more promise but was never fielded.

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    • #3
      Turn up the HEAT

      Thanks for that mfitz.
      However I fail to see how a HEAT round could only have the same penetration as its calibre when it was known from "bench tests" that this just wasn't so.
      Perhaps the developers or government scientists didn't put any effort into it!
      Even so a penetration figure of 76.2mm is still a significant improvement for a weapon that could'n't penetrate anything at all at 1-2000 yards,a range which was quite commonly used by ALL German tanks to hammer our M4s.
      BTW I'm new to this forum(all forums) and am fascinated and truly impressed by the depth of knowledge out there, you being a prime example mate.

      Comment


      • #4
        Originally posted by flash View Post
        Thanks for that mfitz.
        However I fail to see how a HEAT round could only have the same penetration as its calibre when it was known from "bench tests" that this just wasn't so.
        Perhaps the developers or government scientists didn't put any effort into it!
        Even so a penetration figure of 76.2mm is still a significant improvement for a weapon that could'n't penetrate anything at all at 1-2000 yards,a range which was quite commonly used by ALL German tanks to hammer our M4s.
        BTW I'm new to this forum(all forums) and am fascinated and truly impressed by the depth of knowledge out there, you being a prime example mate.
        Welcome to ACG, flash.

        You are asking a good question.

        Couple of things here.

        First up from my own reading, the Germans had a HEAT round available for the 7.5cm KwK37 L/24 (short barrel) tank gun, as carried by the early models of PzKpfw IV. Although the main intended role of this tank was to support German medium tanks in the attack, using 75mm HE to suppress anti-tank guns and other enemy defences, it was foreseen that they would also occasionally have to be able to deal with enemy armour. A standard AP round would not perform very well given the low velocity of this gun. Therefore, a HEAT round - which did not require high velocity to function effectively - was supplied for these tanks. However, its performance was nowhere near the level you have been talking about here and IIRC not as consistently good as the AP rounds used with the longer barreled KwK40 L/43 and L/48; the very reason these guns were used to upgrade the PzKpfw IV to significantly enhance its tank-killing capability.

        Also, it's quite incorrect to say that the Sherman's 75mm M3 was "a weapon that could'n't penetrate anything at all at 1-2000 yards". For example, it was tested as being capable of penetrating the Panther tank at up to the following maximum ranges:

        Turret sides - 1,500m
        Superstructure sides - 400m
        Hull sides - 2,600m
        Turret rear - 1,500m
        Hull rear - 1,500m

        These figures are in metres, so slightly higher for yards. They are from German tables, following tests using captured Shermans. Tests were conducted to derive figures for plates with a 30 degree side-angle to the incoming round.

        OK, so by 1944 the 75mm M3 was no star hole-puncher but its performance wasn't nearly as bad as you seem to be suggesting.


        Page 127, 'Germany's Panther Tank - The Quest for Combat Supremacy', Thomas Jentz & Hilary Doyle, Schiffer Publishing, 1995
        Last edited by panther3485; 18 Aug 12, 02:32.
        "Chatfield, there seems to be something wrong with our bloody ships today!"
        Vice Admiral Beatty to Flag Captain Chatfield; Battle of Jutland, 31 May - 1 June, 1916.

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        • #5
          Originally posted by flash View Post
          Thanks for that mfitz.
          However I fail to see how a HEAT round could only have the same penetration as its calibre when it was known from "bench tests" that this just wasn't so.
          Perhaps the developers or government scientists didn't put any effort into it!
          Even so a penetration figure of 76.2mm is still a significant improvement for a weapon that could'n't penetrate anything at all at 1-2000 yards,a range which was quite commonly used by ALL German tanks to hammer our M4s.
          BTW I'm new to this forum(all forums) and am fascinated and truly impressed by the depth of knowledge out there, you being a prime example mate.
          Test results, particularly "bench tests" are one thing, reality quite another. In the real world HEAT rounds fired from rifled guns in WW2 often grossly under-performed compared to test range results, particularly static tests. Again, the technology just was not there yet. Also, the effective range of a HEAT round fired from the M3 would have been about 200 to 800 yards or under 500 years if fired at a moving target. You only have to look at the PAK 97/38 to figure that one out.

          HEAT was just not going to be the answer.

          The T45 HVAP would penetrate 117mm of armor at 30-deg/500 yards - a substantially better performance.

          The French Brandt company actually was working on APDS projectiles for the Mle 1897 in 1940 when France fell. This would have fired 57mm projectiles from the 75mm gun with a muzzle velocity of 900 m/s and a penetration of 90 mm armor at 1000 m at an impact angle of 35. Again, more promising than HEAT.

          Then there is the Vickers 75mm HV, a gun I have discussed elsewhere in the Allied Armor forum.
          Last edited by mfitz; 18 Aug 12, 05:55.

          Comment


          • #6
            Originally posted by panther3485 View Post
            Welcome to ACG, flash.

            You are asking a good question.

            Couple of things here.

            First up from my own reading, the Germans had a HEAT round available for the 7.5cm KwK37 L/24 (short barrel) tank gun, as carried by the early models of PzKpfw IV. Although the main intended role of this tank was to support German medium tanks in the attack, using 75mm HE to suppress anti-tank guns and other enemy defences, it was foreseen that they would also occasionally have to be able to deal with enemy armour. A standard AP round would not perform very well given the low velocity of this gun. Therefore, a HEAT round - which did not require high velocity to function effectively - was supplied for these tanks. However, its performance was nowhere near the level you have been talking about here and IIRC not as consistently good as the AP rounds used with the longer barreled KwK40 L/43 and L/48; the very reason these guns were used to upgrade the PzKpfw IV to significantly enhance its tank-killing capability.

            Also, it's quite incorrect to say that the Sherman's 75mm M3 was "a weapon that could'n't penetrate anything at all at 1-2000 yards". For example, it was tested as being capable of penetrating the Panther tank at up to the following maximum ranges:

            Turret sides - 1,500m
            Superstructure sides - 400m
            Hull sides - 2,600m
            Turret rear - 1,500m
            Hull rear - 1,500m

            These figures are in metres, so slightly higher for yards. They are from German tables, following tests using captured Shermans. Tests were conducted to derive figures for plates with a 30 degree side-angle to the incoming round.

            OK, so by 1944 the 75mm M3 was no star hole-puncher but its performance wasn't nearly as bad as you seem to be suggesting.


            Page 127, 'Germany's Panther Tank - The Quest for Combat Supremacy', Thomas Jentz & Hilary Doyle, Schiffer Publishing, 1995
            Thanks for your reply PANTHER 3845.
            At what range do the German tests record penetration over the frontal arc?
            This is the nasty end, so to speak, and the part that invariably you'd see first.
            BTW I tracked back through these posts and can't seem to find the results of your very comprehensive "Best tank poll".
            I'd be very interested in seeing it.
            Cheers.

            Comment


            • #7
              Originally posted by mfitz View Post
              Test results, particularly "bench tests" are one thing, reality quite another. In the real world HEAT rounds fired from rifled guns in WW2 often grossly under-performed compared to test range results, particularly static tests. Again, the technology just was not there yet. Also, the effective range of a HEAT round fired from the M3 would have been about 200 to 800 yards or under 500 years if fired at a moving target. You only have to look at the PAK 97/38 to figure that one out.

              HEAT was just not going to be the answer.

              The T45 HVAP would penetrate 117mm of armor at 30-deg/500 yards - a substantially better performance.

              The French Brandt company actually was working on APDS projectiles for the Mle 1897 in 1940 when France fell. This would have fired 57mm projectiles from the 75mm gun with a muzzle velocity of 900 m/s and a penetration of 90 mm armor at 1000 m at an impact angle of 35. Again, more promising than HEAT.

              Then there is the Vickers 75mm HV, a gun I have discussed elsewhere in the Allied Armor forum.
              Hi mfitz.
              I accept all of your points but understand that a round that doesn't rely on kinetic energy ought to be equally effective at all ranges.
              I did say the developers ought to have put a bit more effort into it,lazy sods.
              Did the T45 become widely available, I haven't heard much about it!

              Comment


              • #8
                Originally posted by flash View Post
                Thanks for your reply PANTHER 3845.
                At what range do the German tests record penetration over the frontal arc? This is the nasty end, so to speak, and the part that invariably you'd see first.
                The Sherman's 75mm M3 gun was normally unable to penetrate the frontal armour of the Panther at any range. Therefore, unless you could get an exceptionally well-aimed (or very lucky) shot into an opening, or deflect a shot off the bottom of the curved mantlet down through the superstructure decking, there was little point in trying to penetrate a Panther from the front. (The German tables show zero M as the penetration range; i.e. you couldn't expect to do it.) The 76mm T-34 had the same difficulty.

                The US 76mm gun as fitted to later model Shermans was able to penetrate the turret front at closer ranges, as was the 85mm T-34. The British 17 pdr could penetrate the turret front and mantlet fairly easily at just about any practical range but all these weapons struggled against the Panther's glacis (the main part of the sloping hull front). The Panther was a very tough customer from the front.


                Originally posted by flash View Post
                "BTW I tracked back through these posts and can't seem to find the results of your very comprehensive "Best tank poll".
                I'd be very interested in seeing it.
                Cheers."
                Each of the 12 polls shows its own result, but the overall outcome will be found in my post #74, on this thread:

                http://www.armchairgeneral.com/forum...=122093&page=5

                I only gave a short comment regarding the outcome so far but I intend to go back and say a bit more fairly soon.

                Also, if you go back to the first couple or so posts on that thread it gives you an overview of how the whole thing was designed to work.
                Last edited by panther3485; 18 Aug 12, 11:45.
                "Chatfield, there seems to be something wrong with our bloody ships today!"
                Vice Admiral Beatty to Flag Captain Chatfield; Battle of Jutland, 31 May - 1 June, 1916.

                Comment


                • #9
                  Originally posted by flash View Post
                  Hi mfitz.
                  I accept all of your points but understand that a round that doesn't rely on kinetic energy ought to be equally effective at all ranges.
                  I did say the developers ought to have put a bit more effort into it,lazy sods.
                  Did the T45 become widely available, I haven't heard much about it!
                  I wasn't talking strictly about penetration when referring to effective ranges. The HEAT round has a limited EFFECTIVE range due to its low muzzle velocity. Tanks tend to move. The low MV also results in a lobbed trajectory which of course can change the impact angle substantially depending on range and reduced accuracy at longer ranges.

                  HVAP was never available for the 75mm gun. R&D only, no production.

                  Your contention that the lack of a HEAT round for the M3 can be put down to laziness is an argument from incredulity and has no basis in reality that I am aware of. There was a projectile extant that could have been slapped onto the business end of the 350R case at almost no cost or trouble at all. Problem is, this is a solution no one was asking for. If there is no requirement for such a projectile nobody is going to expend any time, effort or money to create something nobody wants.

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                  • #10
                    One big reason the 75mm was retained was its HE performance. Most Shermans fired far more HE at non-tank targets than AP at enemy tanks.
                    A common role for Shermans throughout WW 2 was acting as self propelled artillery. It wasn't uncommon for the US to line up a whole battalion (54 tanks) and have them firing indirectly as artillery (that's the equivalent of a division worth of tubes). That is alot of HE firepower.
                    That capacity was lost to a great degree with the 76mm.

                    Against lighter armored vehicles an HE common round is more effective too. This could also be used against enemy tanks shelling them at long range in the hopes of getting a suspension hit and taking a track off, that sort of thing.

                    A more effective means of dealing with a Tiger or Panther frontally that many US tankers came up with was the improvisation of firing a WP round into the enemy tank first thing. This had two major effects:

                    First it blinded the target with smoke.

                    Second the noxous and poisonous fumes were sucked into the ventilation fans and into the vehicle temporarily incapacitating the crew.

                    This gave the Sherman crew time to pump several more AP or HE rounds into the target or time to evade the enemy.

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                    • #11
                      It has been a while since I've read up on my HEAT rounds so please, correct me if I am wrong. Doesn't a HEAT round have to hit the armored surface at a certain angle for the concentration of the blast cone to blow through the armor? If I were talking about HEAT effectiveness I should think this would be one of the first things discussed. All shells are fired in an arced trajectory, velocity and range influencing how much of an arc is needed, no?
                      John

                      Play La Marseillaise. Play it!

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                      • #12
                        Keep in mind that not all Panthers and Tigers were discovered hull down and with their main gun pointing at you. The Shermans with low velocity cannon were supposed to maneuver and try for a side or rear shot. The Panther's side armor was certainly vulnerable. Rear shots could take out both cats, but I would try to aim for the engine!

                        The Germans tried to use a new Panzer Brigade structure against Americans in the Lorraine sector. The very experienced (and older equipped) 4th Armor Division destroyed one such brigade and they had Panthers! The better German Generals saw to it that the remains were put into veteran German Armor divisions that needed replacements and equipment.

                        The Germans captured and tested American Bazookas and reverse engineered them. The Germans saw that the size of these Bazookas were too small so they designed theirs to be at least 88mm compared to the American's 57mm. I would say that an American HEAT round of only 75mm would have performance issues against German cats anyway!

                        Pruitt
                        Pruitt, you are truly an expert! Kelt06

                        Have you been struck by the jawbone of an ASS lately?

                        by Khepesh "This is the logic of Pruitt"

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                        • #13
                          Originally posted by JBark View Post
                          It has been a while since I've read up on my HEAT rounds so please, correct me if I am wrong. Doesn't a HEAT round have to hit the armored surface at a certain angle for the concentration of the blast cone to blow through the armor? If I were talking about HEAT effectiveness I should think this would be one of the first things discussed. All shells are fired in an arced trajectory, velocity and range influencing how much of an arc is needed, no?
                          HEAT rounds don't fuse properly at high angles of obliquity, particularly in WW2.

                          Comment


                          • #14
                            Originally posted by Pruitt View Post
                            Keep in mind that not all Panthers and Tigers were discovered hull down and with their main gun pointing at you. The Shermans with low velocity cannon were supposed to maneuver and try for a side or rear shot. The Panther's side armor was certainly vulnerable. Rear shots could take out both cats, but I would try to aim for the engine!

                            The Germans tried to use a new Panzer Brigade structure against Americans in the Lorraine sector. The very experienced (and older equipped) 4th Armor Division destroyed one such brigade and they had Panthers! The better German Generals saw to it that the remains were put into veteran German Armor divisions that needed replacements and equipment.
                            Not the best example given the panzer brigades were designed for the Eastern Front and in the West were an unmitigated disaster organizationally. The German defeat around Nancy in the Lorraine has far more to do with horrible strategy, completely worthless operational planning, and poor tactics than equipment per se.

                            The Germans captured and tested American Bazookas and reverse engineered them. The Germans saw that the size of these Bazookas were too small so they designed theirs to be at least 88mm compared to the American's 57mm. I would say that an American HEAT round of only 75mm would have performance issues against German cats anyway!

                            Pruitt
                            The Germans went with the 88 round because they only had to modify it from their existing round used with the R-werfer 43 puppchen. These were in service in small numbers in Tunesia. The Germans simply saw the US bazooka as more practical and modified their existing round to work with a new launcher like it.

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                            • #15
                              Originally posted by Pruitt View Post
                              " ... The Panther's side armor was certainly vulnerable. Rear shots could take out both cats, but I would try to aim for the engine!"
                              As the tables show, the Panther was clearly quite vulnerable to the sides and rear.

                              The Tiger, on the other hand, was close to invulnerable against the 75mm M3 from any aspect but there were a few weak points you could try. Apart from certain openings which make for weaker spots but are very small, the best weak areas (in terms of actual plate thickness) were the hull sides below the panniers. At 60mm nominal, these were 20mm thinner than all the other main plates on the sides and rear of the tank and certainly within the penetration capabilities of the 75mm M3 gun. The rear on the other hand - turret and hull - was 80mm nominal; usually between 81-83mm in practice; and 'generally' beyond the ability of that gun to penetrate. Also, shots to the side expose the crew compartment and ammo to the direct effects of a penetration and this is the best way to get a kill. (The Tiger might well still be able to fight with a KO'd engine.) Of course, this is only if a clear shot to these side areas is feasible, which wouldn't always be the case. Not to mention that in the heat of combat you might not be able to count on time or opportunity to maneuver. Nevertheless, in terms of the chances of gaining a penetration of plate over an area - rather than attempting 'pinpoint' shots at openings in the hope of exploiting a specific weak point in the thicker plates - those lower sides are your best bet if you can get to them.
                              Last edited by panther3485; 18 Aug 12, 22:33.
                              "Chatfield, there seems to be something wrong with our bloody ships today!"
                              Vice Admiral Beatty to Flag Captain Chatfield; Battle of Jutland, 31 May - 1 June, 1916.

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