According to Hornady the .300 grain .452 XTP magnum bullet is good to 2,100 fps. i've driven it to 1,900-2,000 fps: Bullet goes through both shoulders of a 300 pound wild hog.

Now if we were talk griz. I might understand, but I had no problem taking 2 large and several normal size black bear with .535 PRB and 120 grains of RS Pyrodex. I believe any well placed decent bullet will do the job. Considering the difference in vital areas I would suggest studying a diagram of the vitals and waiting for a broadside shot.
The 245 grain PB is not recommended and if you chose to use PB's I would recommend over 330 grains.