I live in griz country and have had many discusions about what to do if you encounter a griz. First dont make eye contact and speak to it in a calm low voice to make sure it knows your a human. Stand your ground DONT RUN! The whole time getting your peper spray ready to shoot from the hip. I would if the wind is right let off a small blast to scare it. I always carry a side arm 454 casul in case the bear is on top of me. The bear spray is always my first defense because if you shoot a griz any where other than the head he is going to be even more pissed . If you realy want to take a big bore take a 12 gage pump its got more Knock down than most rifles and you can get more shots off fast. Most attacks happen because the people are just be boping along and not paying attenton to their surrondings, and startle the bear at less than 40 yards which they can cover fast ! No time to get the cross hairs on a bobing head and take a chance of wounding it. Even if the wind is wrong close your eyes and spray. some will get him. and blind and hurt it .
Make sure you get a fresh can that has the highest percentage of capcium, UDAP is the best 10 or 15%
REMEMBER BE AWARE IN BEAR COUNTRY! and dont get parinoid, have fun.