GIs's shot lots of 06 in WW2 and Korea, and 7.62 Nato since then. I doubt any loss of hearing from firing a few shots in SD.
I fired a SINGLE .357 magnum round without hearing protection and have high frequency hearing loss in my left ear as well as permanent tinnitus. Just one shot can cause damage, so several shots certainly will.
My grandfather who was a WW2 vet spent his whole life with severe tinnitus and a big old hearing aid in each year. Even with the hearing aids he could barely hear.
Even today, hearing loss and tinnitus are one of the major disabilities reported by veterans when they return home. Couple tinnitus with PTSD and you have yourself a really tough time.