82-BM-37 / M-37 82mm
The Soviet mortar 82-BM-37, or M-37, was presented in 1937 and can be considerer as a copy of the French 81mm Brandt Mle.27/31 model, acquired in small numbers by the USSR in 1936. Soviets built the M-37 with some changes and improvements respecting the basic French design. The caliber was increased from 81mm to 82mm, standard Soviet, and improvements were incorporated as buffer springs between the collar and the bipod, as well as a circular baseplate that allowed more stability when firing. The 82mm M-37 mortar was an absolute success, and has continued in production with minor aesthetic changes, remaining in service in large quantities today.
82-BM-37 mortar gallery and more info