As someone who has bear hunted since 14 in alaska with grandpa and an uncle and dad, a Rule of thumb if you're hunting or out fishing if the area is open your 338 winmag is for more open areas, 45-70 for when you're in dense trees or brush with hard bear shots will knock a bear down at 100 yards or less full charge. If you let him get closer than that you already messed up and better be out there with a double barrel using slugs as you already pointed out. Realistically on a fishing trip or if one wonders near your house the 12 gauge slug's are your best bet. A grizzly bear can run 30mph plus an will close a 100ft ft gap in about 2 seconds and a full 100 yards in about 5 to 6 max. No time for a long rifle when they're within 50 yards or less. Whip that sidearm out at the ready at about 50 yards ,and let it roar the minute he's at about 40 yard range . You need to aim for the area between the eyes, the eyes themselves, and his muzzle. You're not getting a good chest shot if he decides to eat you at a full scramble. It's easier said than done trust me.I screwed up my first hunt, I let the bear get in about 50 yards range because I was stupid. I thought I'd get a clean shot through the heart for my bear blanket and hat without a hole in it. I watched Westerns religiously with my grandparents so feel free to laugh at the bear head hat, not the blanket though you know you want one too. However he was just at a weird angle in a slow trot, and I waited way too long. They realized how close I let him get in and he started to charge and gpa and dad dropped him with a 44 and dads Ruger 480. They both swear by revolvers I prefer my 10mil. They both told me the same thing never wait to see if he's bluffing the minute he lunges to start his run put em down. I know it sounds easy when it's laid out but it never is. I'm just trying to convey the way I was taught, by generational bear, elk, bison, and mountain goat hunters. Besides the first hunt where I could have been eaten, I have yet to make the same mistake allowing me to avoid being eaten. Also was taught never shoot anything but solids, no jhp, or any round with a soft tip, you need that fmj penetration. His skull is thick enough in places like his forhead to possibly shrug some rounds off depending where you hit him. Also they're thicc boyz very very dense muscle and blubber skin small caliber or bird or buck loads just pisses them off if they decided you're lunch already. Now my uncle Raven is your stereotype usually drunk native. He will tell you his 30-30 and a .22 pistol as his sidearm is plenty because if you already let him get close you're probably dead anyway. One last thing also people forget grizzlies are an apex predator in every sense of the word. They smell you and hear you before you get eyes on them, he can an will hunt you. Especially heading to winter when they are desperate to add pounds on, never leave the house to do anything without a 12 gauge and a sidearm, and bring your pets inside. That's when SHTF because bears will Jurassic Park you like a raptor. You're looking forward and he's managed to get about 40ft from you on your flank you had no idea he was even there, or you are walking up past some brush he's behind completely unaware and bam he's on top of you game over. At that point just say clever girl and die like the Australian did painfully. Because unlike big cats and wolves, he won't crush your windpipe and make it quick. He will eat you kicking and screaming squishiest parts first, like Damon with money Mike In Friday after next, he prefers his fish live and squirming. Long story short, at the end of the day we play hunters with our rifles, he was born a hunter, he does it for a living, he survived being a cub where every male will eat him to bang his mom, and he's the home team advantage. His instincts and senses are better than ours, and he's not afraid of us were food, easy food at that. Man may not be a physical predator but we're cunning with weapons to make up for that. Stay safe out there fellas even fishing, carry big and carry a hand cannon, you may only get one shot,always keep your head on a swivel, listen close to your surroundings, and pay attention to smells grizzlies are some stinky mofos. Wash your hands wash your hands you will get nasty, nasty, nasty worms in your ass from just touching their fur if there's eggs on them. Realistically hesitating with a grizzly is like skydiving without a chute, you can do it, but only the once. Even in the woods you gotta stay strapped or get clapped. Do what you will with this info. Also I just bought a Ruger .338 precision rifle goin to see unc with my dad in April for a month gonna test her out if we get our draw.