Your 1.5X-5X will work just fine and they have a good reputation for handling the weather you may encounter.
That said, I bought 1x-4x trijicon last year with the post/triangle reticle and had use for it right against dark on a bull moose....It will stay on my 375.
The Trijicons are heavier and the 20mm [1.25X-4X] is too short for most 375s.
Good luck on your bear hunt!
