They fired to scare bears.
It didn’t work.
I can understand that. Many large predators are not impressed too much by loud noises. Note they were scared of active visuals of people swinging brooms. It’s interesting, because indeed firearms are not real active weapons. You can’t even really see the projectile.
So for scaring, not so good. Possibly stopping them, good.
I recall reading about an experiment someone did with opening an umbrella at a charging bear, and the sudden large object materializing in front of the bear scared it off. I imagine if there was a large predatory face picture on the umbrella (maybe bigger bear face with gaping fangs) that would cause it to pause the attack.