What would be the best DG shotgun to carry while working in grizzly country? Different experiences. Looking at coach guns, but need more info on safeties, interceptor sears, hammer blocks, hammer or hammerless, auto ejectors, sights, etc.

If I absolutely had to use a shotgun it would be a Rem 870 with as short a barrel as legal with a magazine extension loaded with the best quality slugs I could find but there is a better weapon available and that's something like the Marlin Guide Gun in either 45-70 (if you handload or but premium handloaded ammo) or the 450 Marlin if you don't handload....either way I'd put an Ashley rear-sight with the biggest hole possible for the best combo of accuracy and speed.

With respect to any shotgun, the Marlin is shorter, flatter, easier to pack and carries a bigger punch.

I have a Mossberg 500, Stainless, 20", 8 rnd capacity, 12ga 3", with a sling. I think this gun loaded with slugs would be about ideal. It's weather resistant, has a large capacity, the extra 2" from 18 to 20" barrel gives you 2 more rounds in the gun. I had a few conversations with an Alaskan guide cook, she said the gun they had her carry was a 12ga with alternating slug and OOO buck.
FWIW

Having a choice... Id NEVER carry a shotgun for DG. I always hear about guys in alaska toting a shotgun, but where I lived in AK, in southeast, I NEVER saw serious people carring a shotgun. There were a few, but they were generaly people that had occupations that "had to carry". We had this bow-hunting neighbor that lived behind us, the guy was always running around with brown bears, and carried a 4" 66 in 357. This guy was smaller then smallfry and most people called him Tiny Tim.

If I was workign in the bush and needed a nice portable gun for defense, I'd pick one of the 14" barrel Mossbergs or Remingtons.

They're so nice and short, it feels like you are packing a pistol, but with alot more punch.

Load it with BRENNEKE slugs. They are a super penetrating slug, completely different from the regular Foster slugs. I don't think buckshot is very good- I especially don't think the old idea of staggering them in the magazine is a good idea- but some people have had good results with buck at VERY close range.

A rifle is better, but rarely as portable. The Brennekes are expensive, but worth it.