I would go with a premium bullet in the 150 grain range. Branes, use to make their X bullet in 170 grain, they may do still. Anywhere from 150-170 in a premium bullet will get it done. If you already are using 140 grain premium bullets and feel very confident in them, I wouldn`t hesitate to use that also.
THE .270 HANDGUN IS NOT ENOUGH FOR BEAR. IT IS NOT LIKE A RIFLE. YOU LOOSE TOO MUCH VELOCITY AND ENERGY FROM THE SHORT BARREL. CHOOSE A DIFFERENT CALIBER FROM THE MANY THAT T/C OFFERS BEFORE YOU WOUND A BEAR!
I'll start off with I am not a bear hunter.... but....
I'd have to disagree with too little velocity/energy for handgun hunting bear. Yes you will loose some velotity (my guess/testing/reading with other calibers is +/-150 fpm) but thats far from turning it from a .270 to a .243.
If your going to hand load you can make a hot load with a bullet thats made more for bear.
From Lymann #27.... 150 grain .270 at 2850 fpm @200 yards is a "max" game weight of 430#, 100 yds at 582#.