I agree with the posters who recommended the 7x57 (also known as the 7mm Mauser). While I love the 270, I believe the question was of a caliber to use on black bear in Canada -which means woods shooting and I'm just not sold on the 130 gr. (of the 270) as suitable for woods shooting. I'm not saying it can't be used -it's just that I prefer heavier weight bullets. The 7mm Mauser has bullet weights up to 154 gr and 160 gr. loadings the last time I looked (some years back) If you're not a reloader, then outfits like Superior and Hornady will sell 20 round boxes in the indicated loads. I used a 154 gr. 7mm load on a black bear at about 80 yards in Ontario's Nipissing District and he collapsed at the first shot -( the first one I ever shot so I remember the exact details!)
Oh, yeah, I forgot to mention. The penetration is phenomenal. In fact, it's what the 7x57 has been famous for in Africa for decades. Recoil is minimal. ( Being an old dinosaur myself, I can tell you that I remember when the 7mm was referred to as a "lady's gun". This "lady" was glad he carried it for black bear)