My story is the same as Daryl's - bitch is over 15 years old now. She went completely deaf 2 years ago. It all went quite fast - in a matter of couple of months - from normal hearing to complete deafness. I have never shot anything close and over her. It is mostly age related. There can be issues with dogs that have dropped (floppy hanging) ears that are prone to infections - even when treated those are making an cumulative impact on dog's hearing. IMO no hearing protection would save it at the end.

Still plenty left in her even when deaf - yesterday morning