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  • 6-pdr. APDS

    I was looking at the performance of the anti tank and tank guns using the APDS round and am a little surprised that the US never used it. Anyone know why?
    Could this gun have been put in a Chaffee turret?
    (For the what if category, I'd love to see this gun on the bow of a PT-Boat.)
    John

    Play La Marseillaise. Play it!

  • #2
    The US did use some 57 mm APDS. Zaloga says that rounds from British stocks were procured in the fall of 1944, and Vannoy and Karamales assert that, while setting up a defense around Domäne Bütgenbach during the Battle of the Bulge on 17 December 1944, 57 mm antitank guns of the 2/26th Infantry of the 1st Infantry Division had "seven to ten rounds of British discarding sabot (DS) ammunition, which had been issued before D-Day." Green, Thomson, and Roots note, however, "The discarding sabot type of projectile was not adopted by AGF because of probable danger to the user."

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    • #3
      Originally posted by DogDodger View Post
      The US did use some 57 mm APDS. Zaloga says that rounds from British stocks were procured in the fall of 1944, and Vannoy and Karamales assert that, while setting up a defense around Domäne Bütgenbach during the Battle of the Bulge on 17 December 1944, 57 mm antitank guns of the 2/26th Infantry of the 1st Infantry Division had "seven to ten rounds of British discarding sabot (DS) ammunition, which had been issued before D-Day." Green, Thomson, and Roots note, however, "The discarding sabot type of projectile was not adopted by AGF because of probable danger to the user."
      Bold is mine. 'Probable'? The 6pdr Sabot round was awesome. It gave a relatively light weight gun the ability of the 17 pdr against tanks, ie that gun used on the Firefly. I have never ever read that the apds round was dangerous to the user in WW2. I have read that the discarding elements of the round, ie the sleve, may have been a potential problem against supporting arms. That said I have never read that the APDS round ever killed a friendly.
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      • #4
        It's pretty clear what AGF meant was the sabot on breaking away created a hazard to anyone down range of the gun. If there were own troops in such a position, they could be hit by the sabot.

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        • #5
          TAG, agreed. APDS was going to be the wave of the future in about 15 years, but what was observed in contemporary tests were accuracy issues and the apparent danger to friendlies situated in front of the gun. With these issues in mind, HVAP was preferred at the time. That's not to say that no experimentation was done in the US with DS ammo; the NDRC and Ordnance made some headway, especially for AA guns.

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          • #6
            Originally posted by JBark View Post
            I was looking at the performance of the anti tank and tank guns using the APDS round and am a little surprised that the US never used it. Anyone know why?
            Could this gun have been put in a Chaffee turret?
            (For the what if category, I'd love to see this gun on the bow of a PT-Boat.)
            What DogDodger said. IIRC US forces recieved APDS in small numbers when they were part of 21st Army Group and some saved a few rounds all the way into the Ardennes.

            Read all about the latter engagements here: http://www.dtic.mil/dtic/tr/fulltext/u2/a284379.pdf

            Kurt Laughlin found some data on this back in 2002, including what appeared to be an chart for sabot ammunition expenditure by US forces in the ETO:

            On page 4 it covers the 57mm wheeled gun, listing the number of weapons in theater, the number of rounds expended by those weapons, the Day of Supply, and percentages for "APC-T M86 & AP-T; HE-T; and Sabot". All of these numbers are given on a monthly basis, from the 21st of the previous month to the 20th of the given month, as was the practice in the ETO. The data of interest (sabot usage) follows.

            Aug 44 - 7% (of 68,506 = 4800 rounds *)
            Nov 44 - 1% (of 43,024 = 430)
            Jan 45 - 3% (of 84,233 = 2500)
            Feb 45 - 2% (of 79,849 = 1600)
            Mar 45 - 3% (of 75,331 = 2300)
            Apr 45 - 3% (of 52,281 = 1600)
            May 45 - 2% (of 9,349 = 190)
            For all other months the table lists 0%

            (*) Calculation to two significant figures.

            These numbers should be compared with the percent expenditures for APC-T/AP-T and HE-T in the same periods:

            Aug 44 - 56%, 37%
            Nov 44 - 86%, 13%
            Jan 45 - 89%, 3%
            Feb 45 - 61%, 37%
            Mar 45 - 47%, 50%
            Apr 45 - 41%, 56%
            May 45 - 28%, 70%

            There was usage for both of these rounds in every month of the report.

            When one considers the total number of rounds expended over the entire period, the average number of guns in theater, and these percentages, the "average" number of rounds of a particular type that a 57mm gun would have fired over the entire European campaign is:

            200 rounds of APC-T/AP-T
            72 rounds of HE-T
            6 rounds of sabot

            Six rounds in almost a year of combat, and according to the source listed below, the rounds expended figure includes both combat and training. Thus, the sabot rounds might not have even been fired at the enemy. If you look at the monthly figures in relation to the number of guns in theater, only in August of 1944 are the shell fired greater than the number of guns.

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            • #7
              Originally posted by JBark View Post
              Could this gun have been put in a Chaffee turret?
              The the British 75mm tank gun was designed to fit in the same space (cannot recall if it was the same mount?) as the 6-pdr so size-wise it probably could.
              I guess it would depend on the concentric gun mount for the 75mm in the Chaffee could handle the 6-pdr/57mm or be modified to do so. There seems to have been more ooomph in the 6-pdr (max. pressure 46000 PSI, 75mm 38000 PSI).
              On the other hand, the Brazilians and the Norwegians managed to put a 90mm low-pressure gun of French origin into the M24 using the original gun mount.

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              • #8
                Originally posted by cbo View Post
                The the British 75mm tank gun was designed to fit in the same space (cannot recall if it was the same mount?) as the 6-pdr so size-wise it probably could.
                I guess it would depend on the concentric gun mount for the 75mm in the Chaffee could handle the 6-pdr/57mm or be modified to do so. There seems to have been more ooomph in the 6-pdr (max. pressure 46000 PSI, 75mm 38000 PSI).
                On the other hand, the Brazilians and the Norwegians managed to put a 90mm low-pressure gun of French origin into the M24 using the original gun mount.
                The British Ordinance QF 75mm tank gun was simply a bored out 6 pdr. This modification of the 6 pdr was done because the 75mm proved far better as an HE weapon than the 57mm 6 pdr. In Italy the British went so far as to produce the lash up Churchill NA using the gun mantle and gun from a Sherman tank for the modification.
                That led to the bored out 6 pdr using the same ammunition as the US M3 75mm gun did. While this gave the resulting gun a slightly poorer armor piercing performance to the 6 pdr, the improvement in HE firepower vastly outweighed that.

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                • #9
                  Originally posted by T. A. Gardner View Post
                  The British Ordinance QF 75mm tank gun was simply a bored out 6 pdr. This modification of the 6 pdr was done because the 75mm proved far better as an HE weapon than the 57mm 6 pdr. In Italy the British went so far as to produce the lash up Churchill NA using the gun mantle and gun from a Sherman tank for the modification.
                  That led to the bored out 6 pdr using the same ammunition as the US M3 75mm gun did. While this gave the resulting gun a slightly poorer armor piercing performance to the 6 pdr, the improvement in HE firepower vastly outweighed that.
                  Yep .

                  The 6 pdr to 75 mm switch in the British Army more or less proves that the HE round is more important than the AP round as far as tanks were concerned in WW2. Further the US 75mm HE round was awesome and even had better shrapnel effect than the larger 90mm round on the M26. Thus, the 75mm M3 gun remains one of the most unsung weapons of WW2, bit like the KwK 40.
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                  • #10
                    Originally posted by Nick the Noodle View Post
                    Yep .

                    The 6 pdr to 75 mm switch in the British Army more or less proves that the HE round is more important than the AP round as far as tanks were concerned in WW2. Further the US 75mm HE round was awesome and even had better shrapnel effect than the larger 90mm round on the M26. Thus, the 75mm M3 gun remains one of the most unsung weapons of WW2, bit like the KwK 40.
                    John

                    Play La Marseillaise. Play it!

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                    • #11
                      Originally posted by T. A. Gardner View Post
                      The British Ordinance QF 75mm tank gun was simply a bored out 6 pdr.
                      No, it was a new gun designed to fit in the same space as the 6-pdr, possibly using some parts of the 6-pdr.

                      Boring out a gun made for 57x441 ammunition with a 90mm rim to 75x350 with an 87mm rim would be a tad difficult......

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                      • #12
                        Originally posted by cbo View Post
                        No, it was a new gun designed to fit in the same space as the 6-pdr, possibly using some parts of the 6-pdr.

                        Boring out a gun made for 57x441 ammunition with a 90mm rim to 75x350 with an 87mm rim would be a tad difficult......
                        +1 if you can prove that is the case, because everything I've read states that the QF75mm was a bored out 6pdr gun.
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                        • #13
                          The 75mm was definitely a bored out 6 pounder. See below (from Tank Board notes):

                          75mm.jpg
                          "Looting would not be tolerated within the Division, unless organised with the knowledge of C.O.'s on a unit basis."
                          - 15/19 Hussars War Diary, 18th March 1945

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                          • #14
                            Now, that makes for an interesting what if...

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                            • #15
                              Originally posted by Nick the Noodle View Post
                              +1 if you can prove that is the case, because everything I've read states that the QF75mm was a bored out 6pdr gun.
                              I guess it is matter of what you mean by "bored out" and "new gun".

                              The rim diameter for the 75mm round was smaller than that of the 6-pdr, so it seems to me that simply "boring out" would require the boring proces adding material to the chamber walls? That strikes me as odd. The 75mm cartridge was also shorter than that of the 6-pdr and the shape of the two cartridges seems to have been different as well.

                              As far as I can tell, the barrel of the 75mm was externally similar to that of the 6-pdr. I suppose it had to be, in order to fit the same gun mount. But the 75mm barrel appears to be shorter than that of the 6-pdr. (274cm vs 285cm) The breech was similar with some parts - including firing pin and extractor levers - being changed. (according to Hunnicutt, a Cromwell and a Churchill manual).

                              But possibly, they may have started out with the same blank (is that the correct expression?) barrel, then cut and bored them out differently.

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