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German 75mm tank and anti tank guns.

Discussion in 'Weapons & Technology in WWII' started by TiredOldSoldier, Dec 7, 2008.

  1. TiredOldSoldier

    TiredOldSoldier Ace

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    I recently did some research on german 75mm AT/Tank guns and this is what I found up to now, don't know if to post this here or in info request as I don't really believe it's 100% correct yet.
    I tried to group the guns according to the ammo they fired.
    I'm not sure about my English here but by shell I mean the part that actually leaves the barrel and by round the full round including the propellant case.
    For those confused about the cartrige designations so am I :D, taking the 75x243R as example I'm almost sure the 75 is the gun bore diameter and I think the 243 is the lenght of the round (but have no idea how this is measured) and the R stands for "rimmed".

    7,5 cm L/24 short barrelled guns equipped the early Pz IVs and Stugs, and also the PzIIIN.
    This includes two guns
    7,5 cm Kw.K 38 L/24 (pz IV)
    7,5 cm Kannone L/24 (Stug)
    Both fired the same 75x243R ammo but were not identical.

    7,5 cm Pak 40 this was the standard late war A/T and was also, I believe, used on Marders and other converted self propelled AT vehicles. It fired a very long 75x714R round that was unsuitable to handling inside a vehicle. I believe the barrel was 46 calibers long.

    7,5 cm Kw.K 40 L/46 and 7,5 cm Kw.K 40 L/48 is the tank equivalent of the Pak 40, it fired a shorter and thicker 75x495R round with the same shells and approximately same balistics as the Pak 40.This was the gun of the late Pz IV and Stug and I think also of the PJ IV/48. Also some sources call the "short" barrel on the Stug IIIF an L43.
    I believe the Stu.K 40 used in the Stug was very similar to the Kw.K 40 so I lumped them together.

    7,5 cm Kw.K 42 L/70 the gun of the Panther and PJ IV/70, fired a 75x640R round.

    7,5 cm Pak 97/38 this is the French 75 barrel mounted on a Pak 38 carriage and firing 75x338R round, the A/T ammo produced in Germany for it probably used the same shells as the rest of the 75mm family.

    While the shells were designated the same as for all guns I wonder if they really were the same thing.
    - Panzergranate 39 standard base fused ap shell.
    - Panzergranate 40 tungsten cored non explosive.
    - Gr.38 (HEAT)

    I left out the following as not tank/at or marginal:
    75mm infantry guns
    75mm mountain guns
    75mm field guns (and 77mm WW1 guns conveted to 75)
    The 75mm PaK 41 Gerlich squeezebore as it was not put into mass production and you could also argue it was a 55mm not a 75.
    Captured soviet 76mm guns, while the Germans produced ammo for them they were not AFAIK converted to 75mm.

    Next project is giving the 88mm weapons a similar treatment, and the Kriegsmarine had some very unlikely 88s.
     
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  2. Za Rodinu

    Za Rodinu Aquila non capit muscas

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    From forum member Tony Williams, BOOKS BY ANTHONY G WILLIAMS

    "A cartridge is a unit or round of ammunition consisting of a projectile (which may be a bullet, a shell or shot), propellant to thrust the projectile from the gun, a primer to ignite the propellant and a cartridge case to hold it all together. "

    "The term "shell" is again of ancient origin and obvious meaning; a hard outer casing protecting something more vulnerable inside, in this case a high explosive or incendiary compound. In larger artillery calibres, shells can contain a wide variety of materials including smoke to obscure visibility, starshell for illumination, chemicals, various antipersonnel rounds, and anti-tank sub-munitions (some capable of homing onto their targets)."

    "The simplest form of cannon AP projectile consists of a pointed steel shot - the military term "shot" (from the cannon ball era) meaning a solid or very thick-walled projectile, normally without any explosive content (although there were some exceptions, mainly in 19th Century usage when the term 'shot' could be used for APHE). The steel will be hardened, at least at the point, and the shot will have a driving band. The best AP performance is obtained with a rather blunt point, so the shot is sometimes given a "ballistic cap"; a pointed nose cone usually made out of light alloy or thin steel in order to minimise the added weight. Some projectiles were also given a blunt cap of soft steel as this improved penetration against face-hardened armour, leading to designations such as APC (armour piercing, capped) and APCBC (armour piercing, capped, ballistic capped)."

    German tank gun ammunition:

    [​IMG]
    Dimensions are calibre (projectile diametre) x case length.
     
  3. TiredOldSoldier

    TiredOldSoldier Ace

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    Thanks Za,

    The round length baffles me, if it includes the shell (projectile?) a gun would change cartrige designation depending on the ammo it was shooting :eek:. HE ammo rounds for the same gun tends to be shorter than armour piercing (AP, APC, APCR, APBC, APDS, APFSDS and whatever other aphabet soup you prefer) is that how it works?

    What prompted my to post was the discovery, at least for me, that the Pak 40 and Kw.K 40 used rather different ammo and I was looking for confirmation.
    Tony Williams is usually very thorough but in his picture I see no 75x714R and that's one I really wanted confirmation on. As the picture is captioned tank gun ammo and the Pak 40 (barring assorted Marders) is not a tank gun this is far from conclusive.

    The idea of 3 different guns (Pak 40, Kw.K 40 L/43 and Kw.K 40 L/48) which, however similar, are not identical, makes some "discussions" about exact armour penetration look .... :D:D:D:D

    Also from his site is the following, which is unfornulately badly redered, so I can't see where the cartrige case is meant to end.


    [​IMG]
     
  4. brndirt1

    brndirt1 Saddle Tramp

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    The quickest way I can attempt to explain the case length is this; the case length goes from the base/head to the neck where it crimps onto the projectile. If you look at the photos supplied by Za you can see that in at least one instance a "taller" shell has a smaller number. If you then compare the two cases it becomes apparent that the projectile is longer on the taller one, while its case is shorter than it's neighbor.

    It also matters where the case is shouldered so that it fits snuggly into the chamber of the given weapon. If the shoulder is too far from the base the weapon's breech will not close, if it is too close to the base, the breech will close and the round likely fire as well, but the shell will be distorted when the explosive force deforms the case with expansion against "nothing".

    I wouldn't recommend either situation for the gunner or crew.
     
  5. TiredOldSoldier

    TiredOldSoldier Ace

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    Thanks, I think it finally makes sense.
     
  6. Drucius

    Drucius Member

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    You'll note that the short barrelled guns were really artillery rather than anti-tank, so they have smaller cartridges as velocity is less important. The early PzIVs and StuGs were for infantry support rather than battletanks as we understand them now. The short barrelled 75mm L/24 was nothing like the later L/48 gun.

    The calibre is the length of the barrel expressed as a multiple of the barrels width.
     
  7. TiredOldSoldier

    TiredOldSoldier Ace

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    I believe it's more more messy than that, the term caliber is used for both bore diameter and barrel length, and sometimes you find the plural "calibers" for the barrel length wich makes some sort of sense as it's a multiple of the caliber.
    I also believe the the Germans measure that slightly differently from everybody else (they include part of the firing chamber in the length calculation), fso or example the 88mm Flak 18 is called a 8,8 cm L/56 by the Germans but a 88/55 by it's Italian users.
    The whole subject is confusing, I think even many experts don't agree on the terms.
     
  8. Za Rodinu

    Za Rodinu Aquila non capit muscas

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    No, Giuseppe, calibre is the bore diametre, full stop. The "calibres" you say are the barrel length in multiples of the calibre. For instance, a 7.5cm PaK 40 had a calibre (bore diametre) of 7.5cm, and length of 48 x 7.5cm = 3.60m. That is a convenient loose employment of the word.
     
  9. TiredOldSoldier

    TiredOldSoldier Ace

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    WiKi has it wrong as well then, so I'm in (good/bad) company.

    Caliber - Wikipedia, the free encyclopedia

    I now believe the Pak 40 is L/46 while the Kw.K 40 and Stu.K were built as either L/43 or L/48 so barrel lengths would be ....
    Kw.K 40/L43 7.5 x 43 = 3.225 meters
    Pak 40/L46 7.5 x 46 = 3.450 meters
    Kw.K 40/L48 7.5 x 48 = 3.600 meters

    But it gets weirder ....

    muzzle velocity for Kw.K 40/L43 firing PzGr 39 APCBC is 750 m/s.
    muzzle velocity for Pak 40/L46 firing PzGr 39 APCBC is 790 m/s.
    muzzle velocity for Kw.K 40/L48 firing PzGr 39 APCBC is 760 m/s !!!!!.

    This later low figure is because the intitial production rounds charged to reach 790 m/s had a tendency to distort the case and jam so they reduced the firing charge.

    The more I read the less I realize I know .....
     
  10. Za Rodinu

    Za Rodinu Aquila non capit muscas

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    Here you have to be careful as there are variations in definition of barrel length, not all meaning from the front end of the chamber to the end of barrel (minus muzzle brake). I could tell you others but my books are STILL spread among three different garages :rolleyes:

    Not directly related, but read this: Rifling - Wikipedia, the free encyclopedia
     
  11. brndirt1

    brndirt1 Saddle Tramp

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    To muddy the water even further (I hate Wiki for this reason), there is a reference to caliber as a measure of barrel length, i.e.:

    Caliber as measurement of length

    Relationship of caliber in bore and length of gun.
    The length of the barrel (especially for larger guns) is often quoted in calibers. The effective length of the barrel (from
    breech to muzzle) is divided by the barrel diameter to give a value. As an example, the main guns of the Iowa class battleships can be referred to as 16"/50 caliber. They are 16 inches in diameter and the barrel is 800 inches long (16 x 50 = 800). This is also sometimes indicated using the prefix L/; so for example, the most common gun for the Panzer V tank is described as a "75 mm L/70," meaning a barrel 75 mm in diameter, and 5250 mm long.

    Caliber - Wikipedia, the free encyclopedia

    Less or more confused now guys?
     
  12. TiredOldSoldier

    TiredOldSoldier Ace

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    I'm aware of that, It's what I was referring to when I said different armies measured length differently as for the 88 Flak 18 being a L/56 by German measurement but an L/55 by Italian. The difference is even more marked for the naval guns on captured German ships transfered as war prizes after WW1, the Krupp 15 cm /45 guns on Bari/Pillau and Taranto/Strassburg were designated 149mm/43 by the Regia Marina. Still I think the 75 A/T guns used the same measurement methodology so there were 3 different barrel lengths (43, 46, 48).
    The purpose behind the whole research was to give a realistic name to the rounds in my database that sits underneath my ww2 simulation and the final results is that the APCBC rounds will need to be named something like:

    Pzgr. Patr. 39 Kw.K 40 for the 75x495R of the tank guns
    and
    Pzgr. Patr. 39 Pak 40 for the 75x714R of the anti tank guns

    Just for the Pz IV gun I will need:
    7.5cm Pzgr. Patr. 39 Kw.K 40 for the standard APCBC
    7.5cm Pzgr. Patr. 40 Kw.K 40 for the APCR
    7.5cm Gr. Patr. 38 HL/B Kw.K 40 for the HEAT
    7.5cm Gr. Patr. 38 HL/C Kw.K 40 for the improved HEAT
    7.5cm Sprgr.Patr.34 Kw.K 40 for the HE

    and so on for the Pak, the L/70, the L/24 and the Pak 97/38, but as not all guns had all types of ammo this will require more research (sigh).

    I hopefully will resist the temptation to also model the difference between heavy charge 75x495R that jams and light charge that does not but has lower muzzle velocity (even a nitpicking maniac like myself must show some sanity :D:D) I will, I willl, I will ..... (will willpower win?).

    This research seems to show that, contrary to popular belief, at least the German quartermasters were superhumans to be able to deliver the right ammo to the right units most of the time (though I remember at least an episode of disgruntled Afrika Korps tankers receiving barrels of Diesel meant for Italian tanks).
     
  13. Za Rodinu

    Za Rodinu Aquila non capit muscas

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    See my post #8, Clinton :)

    TOS, I'm confused, exactly what are you after?
     
  14. Sentinel

    Sentinel Member

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    So, is the bore measured by the distance between the bottoms of the grooves of the rifling, or by the distance between the lands, or what?

    I'm getting more confused as I go along.
     
  15. Za Rodinu

    Za Rodinu Aquila non capit muscas

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    In Talk:Caliber - Wikipedia, the free encyclopedia
    The calibre for an artillery projectile will be the land diameter, as the projectiles have a driving band of softer metal (used to be copper) to acommodate the grooves and avoid excessive wear as a steel artillery projectile is not as deformable as a lead bullet and can't engage the grooves by itself.

    Also in order to simplify the issue, some artillery barrels have variable groove depth, maximum at bottom, flat before the muzzle.
     
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  16. TiredOldSoldier

    TiredOldSoldier Ace

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    It all started with lookking for historical names for the 75mm ammo, I was really expecting to find only 3 guns, the L/24 the Pak40 and the Panther's with AP, HE and possibly APCR for each .....
    Then I found out there were a lot more 75 in German service that I had immagined :eek: and decided to share that info as I was a bit confused about them (if you look at my initial post I made the "short" version of the Kw.K 40 an L/46 while now I believe it was an L/43).
    Then I found that there were a lot more ammo types available than simply PgGr 39, PzGr 40 and HE so I have some 30+ ammo/gun combinations to look up information about :(:(.
    The exact significance of "caliber" was a side issue I got curious about while searching for info about the guns and ammo.
     
  17. Sentinel

    Sentinel Member

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    Thank you, Za!

    Funny how things get more complicated, the more closely I look at them ...
     
  18. aglooka

    aglooka Member

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    According to my sources the 7,5 cm Pak 97/38 shot its original French and Polish munition. A special hollow charge shell was produced by the Germans to give this rather low velocity weapon a chance angainst thicker armour.

    Aglooka
     
  19. TiredOldSoldier

    TiredOldSoldier Ace

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    Thanks for the info, do you also have the names for that ammo? (they must have called it something to distinguish it from all the other 75mm rounds):D
    I suspect the German produced HEAT would be something like GR.38 HL ... 7,5 cm Pak 97/38 but the original HE and AP rounds are less likely to have received standard designations.

    BTW the 75mm M1897 should be roughly comparable to an US M3 or even M4 gun so not all that poor AP weapon, it should be able to tackle a T34 but would need HEAT against a KV-1 or KV-1e.
     
  20. BWilson

    BWilson Member

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    >do you also have the names for that ammo?

    7.5cm Sprgr Patr 230/1(f)
    7.5cm Sprgr Patr 231/1(f)
    7.5cm Sprgr Patr 233/1(f)
    7.5cm Sprgr Patr 236/1(f)
    7.5 K Gr Pz Patr (p)
    7.5cm Gr Patr 97/38 H1/B

    The last one was the only German-designed shell for the Pak 97/38 and was a hollow-charge antitank round.

    Cheers

    BW
     

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