My friend was hit by the Jacket of a .223 bullet.  The shooter shot a metal hand gun target.  The lead center of the bullet pierced all the way through the target, but the copper jacket peeled back and bounced off "like a golf ball hitting a concrete wall".  The copper jacket hit my friend with enough force to startle him, but did not cause any damage to the skin.

I'm not sure if this is what happened in this video, but it sure seemed like the exact same thing happened except for the gigantic bullet!

Also, Shooting a .50 cal BMG is possible with several guns.  Namely the Barrett.  I'm only 5' 8" tall and it took all my strength to hold this gun up, but I could shoot it relatively easily. (see pic)