In doing "Bear Drills" at a gathering for a number of years I have observed a good number of things that I can share with you guys.
Guys with the totally maxed out loads such as .500 whatevers, .454 Casull, even heaviest .45 Colt loads like 350s at 1400 in 5 shot guns more often than not fail. That is with all the other factors in their favor too. Not being surprised, having clean hands, starting at the low ready, etc. They still usually fail.
Guys shooting loads that will still fully penetrate a Grizzly bear skull, or to vital parts, and yet still be manageable for a competent shooter, using a double action gun such as a Model 25, Model 29 or Redhawk usually do OK. Loads such as 300 grain projectiles in the 1,000 -1150 FPS seem to be the sweet spot for guys to be able to recover from the recoil quick enough to get fast accurate hits, versus just making noise with their guns.
Lots of guys bow up and brag about their numbers, foot pounds of energy this, frontal area that, but the fact is, when you put them on a timer, and give them a series of staggered targets with a small kill zone, simulating a bear charging at you they completely fall apart. It humbles them quite quickly.
You cannot buy experience or skill from buffalo bore. That timer does not care either.
.41 .44 or .45 is of far less importance as is your ability to put multiple shots on target accurately per second.
With all that said, if my goal was to buy a gun purely for protection against bears I was set on a .45 Colt, and I was going to be doing a lot of hiking, I would look for a Model 25 or 625 Smith due to the fact it weighs less than the Ruger, as well as the fact it usually has a little better DA trigger out of the box. I would not be worried at all about shooting one loose.