I have more than 30 years of experience in guiding and hunting big game in Romania. The best caliber ever for brown bear is 9,3x62 minimum is 230 grains bullets.
To be effective on bear hunting you need a bullet of minimum 220 grains.
Safest kill shot is behind the front leg ( classical double lungs shoot) on the middle of the body height. Not to low, not to high. ( specially in the spring when they have a long hair)