Stu.G. lg. 7,5 cm K.

[fert]

Hello,
anyone can help with this gun? I have some data about ammunition but nothing about gun.

any help will be appreciated.

all the best

[Lars Bertelsen]

Hello,
The 7,5 cm StuK 40 was basically a “compact” version of the 7,5 cm KwK 40. The only major difference was, that the recoil brake and recuperator cylinders of the StuK 40 were placed side by side on top of the barrel and not at each side of it. The reason for this was, that the StuK 40 was specially designed to replace the short 7,5 cm StuK L/24 in Sturmgeschützen and thus had to be compact.
The StuK 40 was the most common German tank gun, but I have never seen a good drawing of it.
greetings Lars

[peeved]

Since the cartridge case in the pics is different from the KwK 40's I presume that it is for Sturmgeschütz lang, 7,5-cm- Kanone (Krupp); cf. http://forum.axishistory.com/viewtopic. ... &p=1963503

Markus

[Yoozername]

I believe that is correct. The early projectile design and even the date codes shown for the propellant etc. indicate this as an early design that was superseded by the KWK 40/StuK40 weapons. Given its light propellant weight and velocity and early projectile design, it would not been very good against the T34s, etc.

[fert]

thanks a lot guys!!!

[peeved]

Just to connect some dots, in the AHF link above Spielberger wrote that D-Vorschrift 420/152 was about the Krupp gun ammo and Fert's pics are from D 420/152. Also a 20.11.1941 document Spielberger mentions calls the piece Gerät 5-291. I wonder if the latter is a typo or did e.g. the Gerät Nr. change later since in Gerätliste D97/1+ from 12.4.1945, Gerät Nr. 5-0291 was the 2 cm KwK 38 and Sturmgeschütz lange 7,5-cm-Kanone (StuG lg 7,5 cm K) Gerät Nr. 5-0791.

Edit: According to Waffen-Revue Nr. 83 from 1. March 1942 cover sheets with new and old Gerätnummern for Gerätliste D 97 were supplied and in April the new numbers put to force which may well explain the different N:os for StuG lg 7,5 cm K.

Markus

[peeved]

wk2ammo.com member Nabob has confirmed with a 1943 Gerätliste excerpt that 5-291 was the old and 5-0791 the new Gerät-Nr. for StuG lg 7,5 cm K which together with Spielberger's text tends to attest to the Krupp heritage.

Markus

[Yoozername]

So, this R&D weapon system never made it to production?

[peeved]

AFAIK that is the case; Wonder why the Germans didn't just adapt the Rheinmetall gun for the mid-30's "7,5-cm-Selbstfahrlafette L/40,8 (V0=685 m/s)" and shave a lot of development time off?

Markus

[Yoozername]

Certainly the T-34 and other heavy armored AFV made the Germans do a re-think. Greater velocity and a better projectile was needed. The 7,5 cm Pzgr 39 was the projectile answer and the KWK 40 and StuK 40 and Pak 40 evolved. Capturing weapons like the Soviets F-22 must have had an impact on gun design.

[peeved]

Certainly the T-34 and other heavy armored AFV made the Germans do a re-think. Greater velocity and a better projectile was needed. The 7,5 cm Pzgr 39 was the projectile answer and the KWK 40 and StuK 40 and Pak 40 evolved. Capturing weapons like the Soviets F-22 must have had an impact on gun design.

Sure,

But that was from Mid-1941 on. Since already on 13 October '39 a need was seen for a HV StuG gun: 7,5-cm-Kanone-L/41 ,V0 685 m/s and also some urgency felt since a mild steel StuG with a shootable gun was prescribed for May 1940 it seems odd that an existing weapon was not used. Although most of the eventual delay seems to have been at Daimler-Benz since the first Krupp gun was delivered to them on 30 July 1940 but the prototype demonstrated at DB as late as 19 March 1941, it seems probable that using a gun with the necessary ballistics already developed for vehicular use; Rheinmetall L/40,8 possibly depicted in this photo; would have sped things up.


Although K.Gr.rot Pz. at 685 m/s was operating right on the ragged edge of shell shatter its performance apparently was pretty good for 1940 (And especially for the Mid-'30s when the 7,5-cm-Selbstfahrlafette L/40,8 for some reason failed to go into production). Based on this diagram reportedly from "Vorgänge beim Beschuß von Panzerplatten; Bericht 166" (Lilienthalgesellschaft 1943) at 685 m/s K.Gr.rot Pz. would have penetrated about 67 mm and a Pz.Gr. 39 some 90 mm (Since the Rheinmetall L/40,8 was producing steel shattering velocities with an older projectile it seems probable that its early adoption would also have accelerated 7,5 cm AP shell development). Figures apparently against armour plate at 60 deg from horizontal.


Markus

[Yoozername]

Yes, that is for armor @ 60 degrees. But it is varying the hardness as shown by the Kg/mm^2 numbers. But the K.Gr. rot would have a much more difficult time against armor sloped at 30 degrees such as the T34 front armor.

I believe you got that graph from Matrix games website? I think I posted it!

[Yoozername]

There is another thread going where the 'L41' is somehow installed in panzers. But i will transfer this data I posted there. The 'L41' firing the K. Gr. Rot does not come close to a KWK 40 firing 7,5 cm Pzgr 39...

Penetration values 60 deg homog

*******************100 500 1000 1500 2000 meters
KWK 37
rot.Pz 365 M/s, 41 39 35 33 30 (mm)

7.5 cm Kan L40
rotPz. 685 M/S 65 64 62 59 56

7.5cm StuK40 L43
Pzg- Pg 39 740 M/S 98 91 82 72 63

[peeved]

Continuing in the What-If vein how would you estimate L/40,8 penetration potential with a Pz.Gr. 39 equivalent

Since the Rheinmetall L/40,8 was producing steel shattering velocities with an older projectile it seems probable that its early adoption would also have accelerated 7,5 cm AP shell development

Markus

[Yoozername]

Given the same projectile, I would estimate it having something like 15% less penetration. I am just using the KE by the way.