Well, the problem of range is not that bad with a Thompson Encore, you can reach 200 if you practice. It is only one shot though and if you want six then you need a revolver, and with that you can kiss 200 yrds good-bye. If you have to have six then get the biggest you find. To me there is no such thing as overkill when it comes to bears. Unlike most animals, they can eat you. If you can make do with one shot then get an
encore in 450 Marlin. That should take care of your needs with a range out to 150 give or take.