Most people who saw military service will experience some level of hearing loss from weapons effects and other things like aircraft engine noise. Folks who served in the artillery are a shoo-in for a DVA hearing loss pension and hearing aides. Back in the '60s we did all of our small arms firing w/o ear protection and while wearing steel helmets as an echo chamber to boot. I used to shoot on rifle teams where we didn't have to wear the steel helmet and I can remember my ears ringing for a couple of days after a range session. The Armoured Corps used to issue little ear plugs when firing tank guns. Small comfort when the concussion alone would really ring your bells.