Is there anyway to tell how many of those situations were because of the lack of time to deploy the firearm? Same is true of bear spray. It seems that would have to count as a fail for either defensive tool if the bear is on the person so fast that there is no time of deploy.
From the Smith & Herrero paper:
Firearms failed to protect people for a variety of reasons including lack of time to respond to the bear (27%), did not use the firearm (21%), mechanical issues (i.e., jamming; 14%), the proximity to bear was too close for deployment (9%), the shooter missed the bear (9%), the gun was emptied and could not be reloaded (8%), the safety mechanism was engaged and the person was unable to unlock it in time to use the gun (8%), people tripped and fell while trying to shoot the bear (3%), and the firearm’s discharge reportedly trig- gered the bear to charge that ended further use of the gun (1%).
There were a total of 40 incidents of 269 where the firearm was not fired. The above are percentages of that 40.