As long as it doesn't hit in the eye there's really no danger from a bounce back round. Anyone that has shot on an old indoor range with metal backstops knows what it's like to get hit by one. It hurts like hell and can break the skin but that's all. All the energy is expended as the projectile stops against the metal then a small amount of energy is generated as the projectile bounces off the metal.
He just got hit with the projectile after it bounced straight back from the metal target. Yes it does hurt like hell. I've been hit a few dozen times running classes on older USAF indoor ranges. It's not quite as bad as being hit with a paint gun with just a shirt on. Now if it was a ricochet and depending on the angle of the ricochet then that would penetrate flesh. The lesser the angle the more energy the projectile would carry. People have been killed by ricochets.So technically, he didn't actually get shot; no this has never happened to me, but it still seems as if this would hurt like hell.