85 mm air defense gun M1939 (52-K)

This gun was successfully used throughout the Second World War against level bombers and other high- and medium-altitude targets.

Virtually every country behind the Iron Curtain received this gun after World War II for their air defense.

Military planners directed the design bureaus of both Gen. Vasiliy Grabin and Gen. Fyodor Petrov to modify the 85mm anti-aircraft gun for use as an anti-tank weapon.

Meanwhile, efforts were underway to redesign the T-34 turret to make it large enough to accommodate the newly developed gun.

The resulting guns were tested at Gorokhoviesky Proving Grounds near Gorky, with Grabin's ZiS-53 winning the competition.

Savin was put to work modifying Grabin's gun to fit the new turret and incorporate other improvements.

A ZiS-S-53 at the Arsenal Museum in Zamość , Poland.