The gun in the photo is Soviet 305-mm railway gun TM-3-12 (305/52 ORaut for Finnish military), which was captured in Hanko / Hango peninsula after the Soviets had evacuated their base in December 1941.
The gun in the photo is Soviet 305-mm railway gun TM-3-12 (305/52 ORaut for Finnish military), which was captured in Hanko / Hango peninsula after the Soviets had evacuated their base in December 1941.