[Would you like to see this in-game?]
TL;DR: A KV-1S with an 85mm S-31 cannon. Lost to the KV-85 that we see in-game.
On January 18th, 1943, the Red Army had managed to capture two German Tiger tanks. Subsequent tests with these vehicles revealed an incredibly troubling fact. The 76mm F-34 cannon was incapable of penetrating the Tiger’s side from a reasonable distance. Frantic work immediately began on a more powerful cannon that could be mounted into an armored vehicle. On May 5th, 1943, GKO decree #3289 “On improving the armament of artillery armament of tanks and SPGs” was signed. This decree called for KV-1S tanks to be armed with 85mm cannons. One of the designs put forth advocated for a simple solution: simply mount an 85mm cannon directly into a largely unmodified KV-1S turret. To facilitate this idea, a new 85mm cannon, indexed as S-31, was constructed using parts from the 76mm ZiS-5 cannon. This made the large 85mm cannon’s installation into the small KV-1S turret easier. By May 14th, installation drafts were ready and in mid July, a functioning prototype was ready. This prototype was indexed as Object 238, however, it is better known as KV-85G. The Object 238’s mass had increased to 44 tons, compared to the standard KV-1S’s 42.5 tons, however, this had little effect on overall mobility. Comparative trials were held at Gorohovets Proving Grounds from August 2nd to the 4th. The Object 238’s competitors were the Object 239 and two Object 237s with different guns. The Object 238’s small turret made loading the cannon a challenge. As a result, a maximum fire rate of only 5-6rpm could be achieved. The S-31 cannon itself also proved to be unreliable. Comparatively, the Object 239 could manage a maximum of 10-12rpm. The outcome of the trials was in the Object 239’s favor, which was later accepted into service as the KV-85. An Object 238 survives to this day at the Patriot Park museum in Kubinka, Russia, however, many of its parts are from other vehicles.
Place In War Thunder:
The KV-1S is a fan favorite among lower-tier Russia players. Its decent mobility combined with its reliable armor and punchy cannon make for an incredibly formidable tank. Swapping an already punchy gun for an even more punchy gun with no noticeable loss to mobility would only make the tank better. Of course, a minimum reload of 10 seconds would most definitely make shot placement much more important. Playstyle would be a mix of the KV-85 and KV-1S. You have the mobility of the KV-1S with the stopping power of the KV-85. This would allow for a decently aggressive playstyle. Due to the cannon being in a KV-1S turret, you’d be able to utilize the diamond hull defense to its fullest as you wouldn’t have bulges on either side of your hull. Considering that this vehicle was a failed prototype, I think that the best implementation would be as either a premium or low battlepass reward. I lean more toward battlepass reward as battlepass vehicles are largely heavy modifications of vehicles we already have in-game.
Armament: 85mm S-31 cannon and 1x 7.62mm MG
Dimensions: 8.49m, 3.25m, 2.87m (L,W,H)
Armor: Same as KV-1S in-game.
Ammunition: APHE, APHEBC, APCR, HE
Front View:Side View:Rear View:Turret Diagram:As It Is Today;