What is the decibel of a gunshot?

According to the NRA:

"Gunshot decibel levels, measured by John S. Odess, M.D., ranged between 143.5 from a .22 short to 174.4 from a .458 Win. Mag (American Rifleman, "Hear No Evil," March, 1996)."

Subsonic "gallery" rounds can be as low as 90 decibels, but the average is 133 for all calibers as measured at certifiedreloader dotcom.