139 grain Hornady SST Interlock over 44 grains of H414/W760, over CCI250 primers will give you 2700+fps out of a 22 inch barrel and if you do your part right with an accurate rifle, is very good Black Bear medicine.
I've taken several Black Bears, including a couple over 6 feet, from ranges of ten feet to 300 yards.
The 6ft 4 inch (tip of nose to base of tail) bear was shot at a distance of ten feet. It was a large male, in aggressive/curious mode shot on an alfalfa covered side road. He just wouldn't go away. I already had another smaller Brown phase Black Bear down and was heading back for the quad to haul it out of the bush. I didn't really want this particular Bear or need the meat but it was better than becoming the meat.
The rifle I used for this hunt was a Remington 700 bdl long action, chambered for the 260 Rem in a 22in bbl. I chose the long action because I could seat the heavier bullets at "one" caliber contact depth, without taking up powder space.
I shot both bears that morning with that rifle, shooting that load. The first Bear (5 feet) was shot across a clear cut at just over 200 yds, while it grazed on Dandelion s and the second was only ten feet away. That's about as good a test as you can get for a particular load, with a particular bullet.
Both animals only required one shot to put them down and stay down.
The smaller Bear was shot just under the spine, just on top of the lungs. The bullet took out an angled rib on the way in, ripped the tops of both lungs and severed the two arteries under the spine. It dropped appx 10 yards from where it was shot. The bullet went through the offside, between the ribs and exited the hide, leaving a 3/4 in hole.
The large/aggressive/curious Bear was shot at point blank range. The bullet entered the top of the neck about 3 inches behind the skull/spine juncture, took out a vertebrae/spinal cord and broke up, leaving bits of bone and bullet fragments through the throat/lungs and esophagus. The base of the jacket was found in the right lung. Being a spinal shot, which also took out an artery, the animal dropped on the spot, coughing up blood. The sparkle went out of his eyes before I could put a coup de gras shot into his brain. That skull is looking at me from a book shelf right now.
A flat base Hornady 139 grain Interlock would work every bit as well, but may be a hair less accurate at longer ranges. The flat base would allow more powder room in the cartridge, which might be handy if your rifle has a short action, which limits the length it can be loaded to.
As shotcup says, the 260Rem is a good cartridge for Bears but it's also good for Deer and Moose if the shooter does their part to place the bullet properly.