At the beginning of 1944, the
T-34 tank's
F-34 76.2 mm tank gun was replaced by a more powerful 85 mm gun. This rendered the year-old
SU-85 tank destroyer effectively obsolescent, since its
D-5T 85 mm gun was now also fielded by a more flexible medium tank.
F. F. Petrov's Design Bureau at Artillery Factory No. 9 was assigned the task of producing a 100 mm
anti-tank gun that could be used on the SU-85 chassis, for the proposed
SU-100. To achieve this goal, Petrov's team modified the S-34 naval gun for use in an armoured fighting vehicle. The D-10 is a high-
velocity gun of 100 mm calibre (bore diameter), with a barrel length of 53.5 calibres. A muzzle velocity of 895 m/s gave it good anti-tank performance by late-war standards. With its original ammunition, it could penetrate about 164 mm of steel armor plate at 1,000 m, which made it superior to the German 75 mm
KwK 42 mounted on the
Panther tank as well as the
Tiger I's 88 mm
KwK 36 gun. Testing against Panther tanks at Kubinka showed the D-10T could penetrate the Panther's glacis up to 1500 m. Armor penetration performance increased further with the development of APDS (Armor-Piercing, Discarding Sabot) and other more modern ammunition types after WWII. A more effective high-explosive shell was also developed after the war, taking advantage of the larger 100 mm bore. It was originally designed to equip the
SU-100 tank destroyer as the D-10S (for
samokhodnaya, 'self-propelled'), and was later mounted on the post-war T-54 main battle tank as the D-10T (for
tankovaya, 'tank'
adj.). There was no significant difference in functionality or performance between the two versions. It was also tested on the
T-34,
T-44,
KV-1, and
IS-2 (
obyekt 245). In 1955 a stabilizer (vertical-plane STP-1
Gorizont) and
bore evacuator were added to the new D-10TG version of the gun. In 1956, the subsequent D-10T2S version of the gun began production for T-54B and T-55 tanks, equipped with two-plane
Tsyklon gun stabilization. Versions of the D-10 were installed on new tanks as late as 1979, and thousands still remain in service in various countries. Returning to its naval roots, a version of the D-10 was installed as a coastal artillery piece in Finland in the 1960s. This weapon is designated
100 56 TK in
Finnish Navy service and consists of a complete T-55 tank turret without the stabilizer but furnished with a manually operated ammunition lift, a chute for used cases, and gun laying apparatus allowing indirect fire directed by remote fire control. The maximum elevation of the barrel was also increased and the turret was furnished with new aiming optics, in some cases including a thermographic camera for night use. ==Variants==