How do most soldiers keep their hearing after returning from combat?

I ask this because a couple months ago I went to shooting range for the first time in my life. (It was during one of my friends birthday parties but it was fun). And while I was there the guns were so loud that I could hear them outside the door to the range. I shot with a pistol and a rifle. (Ironically the pistol felt more powerful than the rifle). I had ear mugs on and even with them on it was still super loud. Which came to my mind of how do troops in combat come back without deaf ears?