This sculpture is of Bashkir national hero Salavat Ulaev. He was born in 1754. He took part in Pugachev's country revolt in days of Ekaterina II (1773-1775). The revolt was begun by the Ural cossacks and had been supported by Bashkirs . Cossacks and Bashkirs battled with imperial armies. Therefore the horse skips above a gun in this sculpture. Sculpture is from the 1970's.
There is stamp on the bottom in Russian: Salavat Ulaev - national hero and poet of Bashkir people.
Sculptor is Panov. Here he is on a Soviet postage stamp from 1952