you're a fucking retard, get off my internets.
To the dude who said the recoil would send a person flying... yes, that would be true if he were holding the gun, but the barrett has an anti-recoil mechanism (which I know nothing about) and is also, I imagine, fired on the ground using a bipod. So it gets more complicated.
I don't know about this video, because I can't see it, but think about this:
An 800 grain round fired from a barrett at ~850 m/s would have, by my calculations, ~19000 J of kinetic energy. On the other hand, a 95 grain 9mm round traveling at 300 m/s would have only 276 J.
In other words, the 50 cal barrett round has 68 times the kinetic energy of a 9mm round. That's gonna hurt. I wouldn't be surprised to see little bits of person everywhere.