Interesting, 2 different Glock models 21 and 30, 1911's and S&W .45's.

I think a ported .500 S&W would be my preference on bear-carry. I fired one a while back at the club, with factory Hornady and it kicked less, was actually comfortable to shoot, compared to my 4" m29 shooting 300gr. commercial cast bullets and H110/W296 I had been shooting that day.
I was able to smash 2, 6" diameter granite rocks on the 50 meter bank with 2 successive shots, just standing 2 handed. Seemed to hit well for me and was fun to shoot. My 4" M29 is NO fun with those loads. I had the round butt rubber grip on it that day.

I must say, though, when I was using a 1911 with 300gr. bullets for informal combat matches I put on for the guys I instructed, I had total confidence in the pistol, just as I do in my wheelguns.

The .460 Rowland conversion should be no different, except maybe my right wrist would not be able to handle the recoil. I need more weight in the gun.