So... the bb is accelerated to over 300fps in under a second, so that's like 10g's of acceleration?
Anyways, personally, I haven't been hit in the face yet, but the most painful shot I've had is the calf... the second was the inner thigh. I've gotten hit in the calf twice, and it was extended both times.. the thigh was when I thought my guy had cleared the ridge, so I pushed the lower area, when this dude started shooting at me.. So I ran kind of at him, a little to the side, and he tagged me in the thigh.. If only my hopup wasn't screwed (it overhops with .2's and I haven't swapped it out yet) I would have gotten him.