110% sure eh? Well considering that's impossible I don't buy it. I don't care if the deer is standing still 20 feet away, unless you have a 12 gauge pointed at his head you can't be 110% sure that it will be a kill shot. Weird things happen and it can never be that high of a percentage. 99.9% sure is ok, but there is always that chance that something might happen. Hell, it could even be a faulty bullet that shoots way off target, anything could happen.

I think I'm just trying to say that shooting at a running deer is going to eventually cause a deer to suffer and that there is no such thing as a 100% shot, close, but not quite.....