Bear spray is the first line of defense assuming the wind is at my back or non-existent. The backup plan is 12 rounds of 10mm Buffalo Bore or Underwood handgun ammunition.
The only close encounter I’ve had with a grizzly (and a moose too) was in Canada where I was not allowed to have my handgun. I made a point to not wander more than maybe 25 feet from my vehicle so I could make a quick getaway if needed. The grizzly came within 100 feet of me on a river bank on the opposite side of the Kluane river in Yukon Territory and the moose wandered up river then floated downriver.