Actually three variants of the warhead are documented with original drawings - Ausf. A and Ausf. B shown above, plus the variant with simplified outer shell, let's call it symbolically "Ausf. C". I think, only B and "C" are known to be actually used in existing warheads, B being the most common.
I wonder, could it come from this weapon or its variant?
Curiously, this drawing posted on February 4 calls the projectile as the P 8,8 n.A.: https://www.bocn.co.uk/attachments/8-8cm-rb-_-rh_8_4931_0018-jpg.208011/- the third was a weapon marked as P-8.8, one barrel on a pedestal, the ammunition concept is similar to Püpchen ...) The cartridge has dimensions 89 x 55 R 100mm, the project dated 0.7. 1943 to 0.6. 1944.
I wonder, could it come from this weapon or its variant?