Amongst heavyweights, he's up there at the top. But there are several fighters who come to mind at other weight classes with harder chins in my opinion. Hagler's knockdown, for instance, had very little to do with his chin; it's debatable as to whether it should have been scored as a knockdown at all.
Also, Buster Douglas tagged McCall pretty good a few times in their fight. McCall never went down but he certainly showed the effects of being hit on many occasions. IMO that was Douglas' best performance ever- even better than when he beat Tyson.
Last edited by SBleeder; 11-13-2012 at 10:36 AM.