Have you ever watched the FWP video on using bear spray? Shows a guy spraying that crap out in the woods. Has to spray into the wind to get it to hit where he is aiming and it appears to only go 20'ish under those conditions. You're going to get chewed on if you let a charging bear get to 20' before you react to it. I don't claim to have all of the answers, but I do know that you generally hear that bear spray is the only answer to a charge from those that advocate not killing bears.
