If you are ten yards away from a grizzly and you don’t already have the sights on him, I’m not sure there’s much you can do.
Here is one that was stopped with pistols from 10 feet.
“The bear stood up and growled, like something you would see in a movie,” an eyewitness later told investigators.
From less than 10 feet away, the guide and camp worker drew their .44 and .357 magnum revolvers and together fired four times, ending the 17-year-old bear’s life.
http://gunwatch.blogspot.com.au/2016/10/wy-bear-attack-stopped-with-pistols.html
“A warning shot went off.”
My guess is that they were ready for the bear.
Killing a grizzly is a big deal and killing one gets a close look.
You’d better be able to say it surprised you.
Anyways, taking one down with pistols is close work no matter what. Four shots out of twelve makes them braver men than me.