I've tried it with some success twice.
Both times were when I spotted the bear first.
First time, I spotted a bear feeding in a clear cut in the evening, in early September. I was about 250 yards away, hidden, when I started calling. He looked my way, then started walking down the hill toward my position. My dad is 50 yards behind me trying to keep my dog quiet. He is going nuts, whining and whimpering as he spotted the bear. The bear heard this, and stopped. He must not of liked what he heard or maybe seen, as he turned and ran off. I wish I was packing my 7mm Mag then, I only had my 30-30 as we were mainly scouting for the upcoming moose season. Too bad, he was a good sized bear. /ubbthreads/images/graemlins/mad.gif
The second time was last spring, I had spotted a bear feeding in the ditch along side the road. I crept within 100 yards or so, and got hidden behind some pine trees on the opposite side of the road. I started calling softley, and he started coming my way. I was about to send a 400 grainer home when I heard a truck coming, and it spooked the bear into the bush. My luck, the first truck to drive down this road all day. Oh well, it didn't look to be a huge one anyway. But, I did want to try out my 416! /ubbthreads/images/graemlins/laugh.gif
I have tried calling blindly, but with no luck. Also used it when I spooked a bear while riding my 4 wheeler, they sometimes stop and take a second look.