This was my thought as well. I don't hunt moose, but my understanding is they are larger than, but not harder to kill than elk."Question: Lightest recoiling caliber, available in a gun model that is somewhat adjustable, at least minimally capable of ethical moose/bear shot at 300 yds? "
You own one already.
Now if we're talking large brown bears, that changes things. Honestly how often is the OP going to be shooting at brown bears? I'd buy a separate large caliber rifle, specifically for that purpose