Ok, it seems I stand corrected.
Back in the day when I was in the army I was told that it would take about 100 rounds of 7,62mm on a 1 square meter area to breach the armor of an M113 (not sure anymore if they mentioned a maximum distance for that). Guess they weren't talking AP rounds then. Or maybe the guy was just talking out of his rear end (happened on occasion...). But I find it funny that vehicles designed to protect crew and personnel from small arms fire are still that vulnerable to it. :huh: