Placebo89 said: the reactive armoring of the M1 bears only one hit. the compound who materials of A6 BTW A7 bear more than one hit.
Reactive armor is used against HEAT shells and rockets/missiles, It is not fitted standard to the Abrams.
From the XM-1 to M1A1 the armor was Chobham and RHA, Starting with the M1A1 (Heavy) upgrades, Layers of depleted uranium mesh was also added to increase protection against KE weapons, During GW1 a attempt to destroy a immobilized tank showed that close range 120mm fire was ineffective against the frontal and side armor. It's also likely that the original British composition has been improved on.
The Leopard 2 does not use Chobham armor, I understand that it uses a similar design but forgoes ceramics for extra layers of high-density plastics and steel/tungsten/aluminum plates to increase base resistance against KE hits. This has been upgraded over time with the thickening of sections and appliqué armor for protection against ATGMs.
IMO, There's not really much of a difference in protection for the 4 main western tanks.
Not to, belittle the achievement, but IIRC in that Gulf war case the Iraqi tanks were fitted with steel core ammo which makes for a pretty terrible penetrator against any modern armor when compared to contemporary tungsten or DU rounds.