To help illustrate why missile tanks were a thing, here's what the British thought they needed to defeat the IS-3. They believed the front armor on the IS-3 would be immune to the rifled 120mm on the M103 and the Conqueror (it wasn't, but they thought it would be). Thus, they went big. No, bigger. No, even bigger than that - they took the Conqueror hull and slapped on the 7.2" howitzer to make a 183mm tank gun. The gun was only outfitted with
HESH ammunition in two-piece format, with a 72.5 kilogram shell and 33 kilogram propellant charge. While the tank version was never built, the FV4005 tank destroyer tested the gun, but before the tank version could be manufactured the introduction of the Malkara ATGM with its 203mm HESH warhead launched from Humber Hornets made it clear the entire concept would rapidly become obsolete.
FV215
Fire Control: +1
Stabilization: None
Armament: 183mm L4, M2 roof mount, M1919 coaxial
Ammo: 20x183mm, 950x12.7mm, 6000x7.62mm
Fuel Type: G, A
Veh Wt: 66 tonnes
Crew: 5 (commander, gunner, 2 loaders, driver)
Mnt: 22
Night Vision: Headlights
Tr Mov: 90/54
Com Mov: 15/9
Fuel Cap: 1137
Fuel Cons: 500
Config: Veh
Susp: T:6
HF: 75
HS: 15Sp
HR: 10
TF: 76
TS: 5
TR: 5
183mm L4
Rld: 4 Rng: 325
HESH: C:54 B:37, Pen 34C
Note: reload is with 2 loaders. With 1, double reload time to 8.