The Simple Noise Prediction equation can be used to predict the distance at which *140dB of sound could be expected to be achieved.
*Note: 140dB is the environmental noise level exposure at which permanent hearing damage can occur even with short-term exposure. This is also the loudest level of exposure recommended given the aid of hearing protection devices.
Noise Comparison:
125 dB - (Hearing)Pain begins
140 dB - Jet Engine at 100 ft.
194 dB - Loudest Sound Level that Can Occur
Resource:
"Formulae for Ammunition Management." International Ammunition Technical Guideline. 1st ed. New York: UN, 2013. 2-3.UN SaferGuard. United Nations Office for Disarmament Affairs (UNODA), 20 May 2013. Web. 12 June 2015. <http://www.un.org/disarmament/convarms/Ammunition>.
This equation, Simple Noise Prediction, references 1 page