Shell ID help

[Fritziii]

Picked these up this morning at a local flea market, both are WAa and one is dated 1936 the other K, can someone tell me what weapon these are from?

Fritz

[Fritziii]

Here is a pic of one of them standing up, both are the same size.

[Fritziii]

The shells measure 5" tall and 3" in diameter.

Fritz

[Fritziii]

Wow, no thoughts? Could they be for a PaK ?

Fritz

[racefiets]

The case is for 7,5 cm Geb K 15 and 7,5 cm Geb K 14 Kp.

[Fritziii]

The case is for 7,5 cm Geb K 15 and 7,5 cm Geb K 14 Kp.

Thanks!