I think a lead ball of that size, shot at a small dear (providing it had the force behind it) would be enough to crack open a skull, weather it would be enough to penetrate I don't know, but a well placed shot only needs three pounds of pressure to knock-out, maybe five-seven to kill. I have a personal dis-taste for Bear, I study bushcraft and survival and I think his shows are not for either, though he is obviously ex-military and has some skill; I think Ray Mears said it best "Bear Grylls is a showman and I'd hope my audience can see the difference between our shows." You know his cameraman (Bear Grylls') once showed everyone a receipt for a hotel, during the time when he was supposed to be staying out in a camel skin, and the same man also said they would shoot a mile or so away from town; I just think his shows are badly put together, with conflicting and almost useless information a lot of the time. He seems like a nice enough man though.