Description and photo posted by “Pigeon 3175”:
Quote- " 3in Mk7
The factory stamp (?) Is DY (edit, JDY)and Daikin’s Yodogawa Factory, and the charge stamp (?) Is AC (edit, JAC) and it seems to be Asahi Kasei’s Oita factory. The explosive tube is not clearly engraved, but it has a thin CE letter and is thought to be made by the Etajima factory of Chinese explosives. Made in 1982. "