I shot my team mate point blank in the back of the head with a .46g out of my 490fps BASR. I wasn’t in his good books for a few seconds, until he realised he walked in front of my barrel just as I pulled the trigger. (He’s short so I didn’t see his head in my sight....)Wasn't me but a sniper buddy of mine had a lad literally jump in front of him 5 meters in front as he pulled the trigger. Was a "proper" 500FPS sniper with 0.43's. Dropped the lad like a sack of doo-doo but he jumped back up and ran off. Later on at lunch he'd got what looked like an egg on the side of his head. Very lucky it didn't penetrate at that distance.
The above was a bit of an isolated incident though, generally I tend to move myself away from the main "cluster" and go for the angles or a "long walk" round the edges to try and get the drop on enemy. You can get a few decent hits sitting behind the main cluster but usually a decent opponent will be well dug in and difficult to hit straight on.
He did mention something about a headache, but after giving him a dose of the man ups he was fine.