Have you considered building a fire while processing game after dark? Not that I've tried it as only just now considered it and we have a lot of work at hand already without building a fire. I'm not sure if it helps or not but it makes me feel better when I have a fire at my back. I guess I don't really know if anyone has been attacked by a bear or not while in close proximity to a fire. I'd be interested to if anyone else has info on this.
Other than the benefit of the light the campfire would provide for purposes of seeing my gun sights, I wouldn't expect the benefit of bear deterence. At least not for the bears that are apt to maul and kill. But I have no knowledge or stories that relate to the bear deterence value of campfires. No armchair knowledge either.