OK...have spoke to lots of guys and looked at lots of data.
We know shot placement rules, that is a given, and bullet construction 2nd...given those things are taken care of, and all else equal;
what would you rather have in your hands & why, when a grizzly charges from 50 yds. or less...
a .50 Alaskan lever-gun or a .416 bolt-action rifle, not just the "action" type, but even more so the CALIBER?

At 50 yards the rifle accuracy isn't as important as the shooters accuracy, so the inherent accuracy of a bolt gun is lost.

again if a griz is charging, you will only have time for one good shot...so the faster lever action plus is gone.

Either the 416 rem (or Roy) is plenty of gun with a good shot. So is the 50-348 IF that is what you mean by the 50 Alaskan.

416 bullet selection is probably better than any 50 cal bullet selection. so the 416 gets the nod....I like the 400 grain FMJ Hornady in a 416 mag.

All my bear have been killed over 50 yards, and the 50 yard ones were heading away...fast. I hunt a 416 mag. with a 400 grain hornady in the rem mag and a 350 grain Speer mag-tip in the 416 Weatherby.

My big lever gun is just a 348 win m71. But i trust that at 50 yards on a inland griz with some good handloads (most factories are 200 grain deer loads)

I really don't see a difference, it would depend upon the shooters comfort level.

Ok, yes, so your experience and what you are talking about is mostly when you are hunting the bear...
I was talking of the reverse, and I have heard the .50 cal. is a fantastic "stopper" and low velocity with a heavy hard-cast is better than high velocity as in the .416. I know the .4xx are great for penetration of tough skin DG as found in Africa, but bears are not that...just ferocious, tenacious and mean and thought maybe that the bigger hole, the larger wound channel may give an advantage, dunno?

not hunting either rifle is too heavy to carry any distance with other outdoor activities. Pepper spray is a better carry/deterent...and it doesn't raise charges or shooting a grizzly illegally. Usually, a 50 yard dead grizzly (aka 'charging') will bring charges and investigation.

bled out is a thing that likes a large blood channel. charging animals don't give a person a chance to see it bleed out. You want full penetration, so FMJ or stout bullet woould be the thing to use.

i know that a lot of bear investigators like the Model 1100 with slugs , IF they had to stop a charge, heavy slugs and 5 shot capacity. And it can be loaded with rubber bullets it one desires.

Our Sitka brown bears can motor along at 30-35mph when the mood suits them, and they're agile as cats, but for an unlikely though possible in-your-face HOLY S**T! bear encounter when we're out hiking or berry picking I prefer carrying a Remington 870 Magnum loaded with slugs, even though we do have a .375 H&H and .416 Rigby in our gun racks. We also carry pepper spray - horrible stuff (mind the wind direction) but it does work.

Just for the heck of it I did the time and distance math for a Sitka brownie charging at 30-35mph from 50 yards out. From the time the starter's flag dropped you'd have half a ton of bear arriving in your lap within 2.94-3.57 seconds.

Then, in that case, I would want my Benelli M2 3Gun or my M4 H2O loaded with Brenneke Black Magic 3" magnum slugs to put the best 6 or 7 aimed slugs in that bear ( in 3 seconds, the Benelli can fire the whole 8+1 mag) easily.

Good choice. Our PD responds to "naughty bear" calls on a fairly regular basis. Generally these involve nothing more than a garbage can that's being turned into a chew toy by a bear rummaging for leftovers, or a momma with cubs taking a shortcut through someone's yard, but the possibility of things going sour is always there. Thus, when responding to these calls a 12ga is always close to hand, and I believe the slugs they're loaded with are Brenneke Mags.

Are you with the PD there?
Glad to here it...I get lots of flack, on other forums when I mention SG's & Brenneke or Dixie slugs.
The armchair rocket scientists or rather "Great White Hunter" bwana chiefs ...say SG slugs are not even close to rifle rounds, something about "sectional density" but I believe that Brenneke are very much like hard-cast and have deep penetration?

Nope, not PD, just a retired gunsmith. Living on an island that boasts 14 miles of paved road and a small population you get to know the details of how things work.

Nmckenzie spot is on bears can flat move when they take a notion and 12 gauge is hard to beat up close and personal.Ihave a few mining friends that swear buy shotgun.One of my friends mining cohort.shot a bear breaking into his cabin(shotgun)Nuisance bears if t hey can't be run off they'll use a shotgun or rifle whatever the situation dictates.The 416 or 50 alaskan?Either will do the job,this being hypothetical question,probally the rifle I could handle the best.I spooked a few bear while hunting,stalking moose.ONE encounter particular encounter stands out while hunting.I was walking back from stand at dusk when I heard some thrashing about.I thought it might be a bull so I went to investigate.I come around a bend on a trail I walking on there's about 7ft bear about 25 -30ft away.I pull up my rifle he or she notices me..I think should I or shouldn't I shoot it.It took off like a shot plowing thru willows and birch trees ,sapling like it was grass.I had my rifle shouldered and would got off one shot if it tried to go at me.AND if I didn't have shouldered and came at me....There was no way I'd be able to get off a shot.Most bears will avoid human contact.I could go on and on but I'd be getting off topic

I have shot a lot of big game animals with a .416-Remington magnum in a model 70 Winchester but when it comes to Big Bears, I like the added insurance that the .458 Winchester mag gives or it's big brother the .458-Lott caliber. It makes a bigger wound channel, hits harder and more kinetic energy to the animal.

The question there is not how fast the gun will fire; it is can you bring the gun into a shooting position and hit a target moving over broken, wooded ground at 30-35 mph. Preferably you want your hits in the CNS.

__________________
"Only hunting and mountain climbing are sports. The rest are just games."