Quite a few guy's I know use 500-600 lb shrugs off a rack. A personal friend of mine does 900+ partial shrugs for rack training. And as TexR said, untill doing 70lb DB preacher curls, the arms didn't advance much. That same personal friend of mine does 120+DB preacher curls now and than just to test his arm strength (had not done any direct arm work at all in any regular training). Some guy's just seem to need that max weight (for them) to get bigger. Or if some of theses people change the rep scheme & reduce the training time, they tend to again add muscle growth .
Risk? I can't believe a guy from Texas would be concerned with risk or getting hurt. They would have you believe the have real men down there, from what I heard. Balls to the wall, kind of guy's. Let's not have any more sissy talk about risk or getting hurt from any guy from Texas. (Though I did play in a game against some guy's from Texas...tough arse line play) Good Luck.