Remember those super-powerful 85 mm and 107 mm pre-war gun projects? The ones aimed at super-powerful tanks potential enemies of the USSR were allegedly developing? By 1942, the Soviets got tired of waiting for those tanks to show up, and scrapped the whole thing.
CAMD RF 81-12038-50
"By the order of SNK USSR and CC of the Communist Party #P32/116, dated May 14th, 1941, Molotov factory #174, Order of Lenin, produced a prototype of a 107 mm anti-tank gun (using the mount from a 152 mm model 1937 gun).
Trials of the gun and its ammunition were carried out on the Tagil proving grounds, from November 29th, 1941, to January 12th, 1942.
The ballistics requested in the tactical-technical specifications were reached (muzzle velocity of 1020 m/s), but the penetration of 160 mm was not, due to insufficient robustness of the armour piercing shell hull.
According to the conclusions of the Artillery Committee of the Red Army GAU, the 107 mm M-75 anti-tank gun, due to unsatisfactory performance and reliability of receiver and semi-automatic components, insufficient barrel life, and insufficient mount lifetime, the gun failed trials.
As the experience of the war did not confirm the need of this sort of guns in order to combat tanks, I deem it unnecessary to continue development of the M-75 gun or its ammunition in order to get rid of these defects.
As a result of the above, I ask for your permission to terminate work on all work on the 107 mm M-75 gun and analogous work of Stalin factory #92, Order of Lenin, on 85 mm and 107 mm ZiS-23 and ZiS-24 anti-tank guns.
Deputy People's Commissar of Defense of the USSR
General-Colonel of Artillery
April 4th, 1942"