Vega,
45 long Colt will kill black bears as long as you place your shots accurately.
One or two summers ago a Arizona camper killed a attacking black bear that mauled him in his sleeping bag with a Ruger Vaquero 45LC. He was sleeping on a cot under the stars and the bear came in and tore him up. In the dark he couldn't find the gun he'd had near him or see what was attacking him. He hollered for his brother to turn on the truck lights, wiped the blood from his face and saw the bear a few feet in front of him. He shot the bear dead. As I recall this guy's a cowboy action shooter from southern Arizona.
I used an original 1873 Winchester that was well worn and shot out so I had it converted from 44-40 to 45LC and also cut to a short rifle. It was barely ready to use and I had just sighted it in with 225gr SWC lead bullets over 7.5gr of Unique, a pretty light plinkin load. This 300 pound black bear was killed with it. The bear was coming down a tree head first, left front leg extended ready to smack me or a dog. Since he was above me the 1st shot was put into the base of his throat and went upward into his chest area. The bear turned on the tree and I put the 2nd shot into the armpit, he went to a limb and I couldn't see anything but his butt so I hit him in the right hip. He fell and hit the ground dead. I think it had taken about 7 to 10 seconds for the 1st two bullets to take effect.
I think a charging sow, with cubs who is bent on getting to you, that would require something substantial. Like a heavy loaded 44/45 or better a 12 ga slug, or a 20 ga slug put in the right place and another quick shot for good measure.
The Cabela's Millenium is a Italian copy of a Colt SAA and will not take the loads of a Ruger which is a magnum frame. If your not stuck on the 45LC cartridge a better choice for reloaders is the 44 special. It's case is not as fat and therefore the cylinder has more strength. In a Colt SAA size gun it's not as large to carry around as a Ruger and still give you 1000+ FPS.