I don't think it's dangerous either, but I will say that for people without a history of shooting, firing a hard recoiling rifle will help them develop a flinch. I've shot M-14s with the standard steel butt-plates, and after a few hundred rounds, your shoulder begins to get sore. That's not the case with my Fed Ord.
Mark
You're on the ball, mate. Who cares about a bit of recoil, it's only natural. What's more important to me is the properties of the ammunition, and in my opinion, the 5.56 only does half the job. Whatever you hit with the 7.62 (.308) goes down and won't get up, and that's the bottom line. Most of the people I know that were trained with the 7.62 would be more than willing to carry the extra weight because they know the capabilities of the weapon justify every little bit.