There are no guarantees in life. All you can do is prepare the best you can.
Grizz? A Ruger Alaskan in 454 casull Or .480 Ruger will kill a grizz. Question is would the mortally wounded grizzly kill you after you shoot?
Hopefully I’ll never have to find out.
Every year for seven years I’ve spent several weeks each summer on the Yukon River alone either in Yukon Territory, Canada or Alaska. Late one night over the gurgling sound of the Yukon I heard what were clearly bear noises like grunts and groans and roars. (I heard it because you don’t sleep real well by yourself on a Yukon River bank.)
I always have a cold camp and never cook anything where I sleep. So, my guess (at the time) was it was a random bear and he had not seen me or smelled me. Anyway, I saw him across the river which at this point was only about a thousand feet wide. On me I had my .500 S & W Magnum and my Remington 870 Tactical loaded with 000 Magnum shells.
Fortunately for me the bear just hung around in the river about ten minutes and then ambled back off into the woods.
I made my mind up during that ten minutes that if I was forced to kill the bear I would not report it just for stupid laws and regulations like this one.
Fortunately, I did not have to but it was the hairiest ten minutes of my life.
Oh, some of you may not know that it never get’s dark on the Yukon. It gets down to a sort of “dusk” that you can clearly see in. Sun’s back up between 2 & 3 a.m. Goes down after midnight.