This is some what of an old report and it was sorta discussed earlier in this thread but this is a report from USAF Today:
U.S. News & World Report
June 9, 2003
Washington Whispers
By Paul Bedard
M1-A1 Abrams: tough to kill, but not invulnerable
They call them "lessons learned" reports in the Pentagon, and few are getting as much attention as the review of the Army's lumbering M1-A1 Abrams tank's performance in Iraq. Revered by soldiers as the world's best, the report found that lone Iraqis armed with simple rocket-propelled grenades halted a few Abramses in their tracks. Just like those Battle of the Bulge scenes of GIs firing at the bellies of Nazi tanks, a rocket aimed at the armored skirts on the side and back of the Abrams would occasionally disable the tank. That's led some to question the plan to replace some M1s with lighter and thinly skinned "Stryker" vehicles. But then, the report shown to Whispers also found that the heavy Abrams guzzled more gas than expected. And getting parts to busted tanks was a problem. Still, like the Terminator, it didn't die easily. Some completely disabled tanks were abandoned, and airstrikes were called in to keep the gizmos inside from Iraqi spies. It took a grenade detonated in the crew compartment, a massive tank round, and two precision Maverick missiles just to put one down.
"Here's a 2nd hand account from a Hawg Driver:
"I know the guys who shot the mavericks into that tank- also know guys who fired them into broken down helos so that the Iraqis couldn't get the gizmos inside. Here's a story on the Abrams toughness- the two guys go out there (at night)- the army tells them they want this disabled tank destroyed- it's night, and we don't have targeting pods, so the most precise weapon to use is the maverick (reason we didn't use 30mm) So the two guys put their mavericks into the tank- we all watch the video, you can see the splattered "hot molten ju-ju" when the wingman fired into the tank all over the road- the damn thing looked like it was completely destroyed. The next morning, Fox news has footage of the "destroyed" tank on TV- no shit the thing looked like it had just been painted black- there was no considerable damage- not like when we put a maverick into a Soviet-built tank- the turrets pop off, those things just fall apart. Not the Abrams. The guys who fired the mavericks were pissed that they couldn't destroy it, but damned impressed on the same level. Yes, the thing can be immobilized by well placed shots to vulnerable areas- as for obliterating the thing... I don't think it's possible."