The 9 cm mortar Type GR (German-Russian) was a World War I Russian mortar, developed circa 1915. It was a variant of captured Austro-Hungarian mortars 9 cm Minenwerfer M 14. 12,519 9 cm GR mortars were produced in 1915âÂÂ1917 in Russia. Its shell is comparable in power to the modern 81 mm mortar shell.