Hello, wonder if anyone can help me with the following information? - did the hearing protection issued to the army change at some point in the 1980s/1990s? I have heard something along the lines of it changing in 1991??? - if so, when, and from what to what? - is there any research about the efficiency of hearing protection issued in the 1980s/1990s, particularly in relation to pistol fire? Thank you very much to anyone who can help!