The IS-2 tank debuted in early 1943, and, judging by collected combat experience, still enjoyed relative immunity on the battlefield until the end of the year, both against enemy tanks and anti-tank weapons.
"The resilience of IS-2 armour allows it to openly engage enemy heavy tanks at a range of 1000 m. Irreparable losses only happen as a result of combat with enemy heavy tanks in ambush at a range of 300-400 meters. There were no losses from Panzerfausts, only minor damage (road wheels, suspension arms, tracks."
Via Andrei Ulanov.