I saw some posts here that explained different noise levels of different guns/bullet calibers. I have also seen the chart. My question is..... How much does the noise drop per foot / yard (or whatever measureing distance). My questions arose because I was at the range the other day (outdoor range). I was in the back area, about 50-60 yards away from a pistol shooter who was at the front end of the bay. I was not wearing hearing protection when he begain to fire, and although it was loud, it was not painfull or nearly as loud as being right next to a gun. Soon after that he backed up more and started to unload his ar-15 about 15-20 yards away. This was substantially louder and I quickly put on my ears. This leads me to the question of how far away is an average distance that is safe to not wear hearding protection? Next question, how much does the terrain effect the distance the sound of a shot travels? For instance, I would assume that in a desert the sound of a shot would travel further then in a hilly wooded area where there is more of a dampening effect. I know there are several members here that have experiance and knowledge in the audio arena. Thanks in advance to anyone that responses.