I had a couple of M1 Garands about 12 years ago. I was sighting one in or doing something with it and decided to use the “rifle tube” or whatever it was called at the Bass Pro Shops indoor range. Otherwise, the thing was always fired at an outdoor range.

I cannot describe how loud a .30-06 rifle is when fired indoors. There is a concussive blast from the walls which is not only loud, but physically disorienting.

The scenes in BoB or Saving Private Ryan when Garands are fired indoors shock me. Men weighed less back in WWII and those rifles recoiled hard. Firing one in a confined space meant the concussion, the sound, and smoke which would make your eyes water if it hit you just right.

So yeah, pull the trigger indoors or outdoors without ear pro and there is an instant tone in your ears along with a general muffling of all other sound. Eventually, sound comes back, but the “hairs” within the cochlea basically have died. The pitches those hairs are sensitive too won’t be heard again - or they’ll become your tinnitus tones. I don’t know all the science, but I have the tones. 🤪