The L-11 was a 76 mm tank gun. It was designed at the Leningrad Kirov Factory design bureau by I.A. Makhanov. It was used on T-34 and KV-1 Tanks.

How to Get L-11 76mm
Tools + Morozov

L-11 76mm Doodle Tanks Combo
+Grabin = F-34 76mm
+F-34 76mm = Shelling
+T-34 Hull = T-34 Model 1940