No, your ears never "get used to it". Loud noise is always damaging. Hearing loss usually shows up later with the continual assault of loud noises. A VERY loud noise can cause almost immediate damage.
Back in my younger days, I stood next to a .357 snubbie (about 10') on an outdoor firing range for 50 rounds with no hearing protection. Now I have a 50% loss in that ear over the other one.