A revolutionary feature of the T-64 is the incorporation of an automatic loader for its 125 mm gun, allowing a crewmember's position to be omitted, and helping to keep the size and weight of the tank down. Tank troopers would joke that the designers had finally caught up with their unofficial hymn, "Three Tankers"—the song had been written to commemorate the crewmen fighting in the Battle of Khalkhin Gol, in 3-man BT-5 tanks in 1939.Три танкиста (Three Tankers)
