The gun is a rifled one, not a smoothbore - the performance for KE is worse.
By the fabricant very best estimates, L28A2 APFSDS - the latest ammo - is maybe comparable to M829A2.
But how much worse? For one it is a L55. M829A2 is still one hell of a round.
A difference of 20% of engine power is not small.
Not when we are talking of a vehicle with the power/weight ratio of modern MBTs, they hardly ever need to make use with more than half anyway, things like torque and transmission are more important variables here. Ironically T-90s have similar p/w ratio to Challenger 2, varying with models, yet no one goes around calling them underpowered.
Newflash, Russia isnt Iraq. Russia has modern optics, laser guided artillery, drones, cruise missiles, good guns and modern anti-tank rockets.
In advertising catalogues, sure. On the frontline, these are nowhere near as common nor high quality as they would wish them to be.
Also vast majority of their tanks don't have good enough guns against Challenger 2's frontal armor. The latest upgrades of T-72/T-90 that can take extended length APFSDS are the only ones that may have a chance.
Also who uses cruise missiles against tanks LMAO.
If houthi rebels can kill Abrams, and Kurdish militias can kill Leopard IIs, The russians arent going to be overly bothered by a handful of Challenger monkey models.
These aren't monkey models, but UK's line tanks.
And yes, anyone with properly used half decent infantry anti-tank weapons *can* kill any tank, but the *can* metric is for practical purposes of little value.
Likewise T-72B3's *can* be killed with a WW2 style anti tank grenade, properly applied in the perfect circumstances of course, no need for even a bulky RPG, if we are going to have an exchange of pointless disingenuous arguments.
But that doesn't mean at all it's easy or that it will happen often, like you are doubling down on here.
Even 50 or so of them will make one hell of a breakthrough battalion.