I've been researching the topic about what makes one gun louder than another for quite awhile and have found something very interesting that I wanted to share, although it may actually be old news to some (maybe even most?). But I thought it was interesting.
I always thought it was about decibels. The higher the decibels, the louder a gun sounds. However, an AR15 with a 16" barrel sounds a lot louder to me than a 12ga. shotgun, even though charts show them to be about the same, with the AR often being maybe one decibel lower. I've also been around short barreled .223 guns that blew me away with the noise they made!
Then I came across an interesting PDF file that shows the decibel range of AR15's with barrels from 5" up to 24" and discovered that the decibel rating is nearly meaningless. It's page 14 of this file: https://ndiastorage.blob.core.usgov...0/armament/WednesdayCumberlandPhilipDater.pdf
There's only a difference of about 2.5 decibels between a 5" barrel and a 24" one, although your ears would tell you otherwise. The sound of even a 10" barrel is in no way anything like a 24". However, check out the pressure ratings in that chart. The 10" pressure is 12,400 and the 24" pressure is only 4800.
It would seem that it's the pressure in the barrel at the time the bullet leaves the muzzle that determines how loud a gun is.
I always thought it was about decibels. The higher the decibels, the louder a gun sounds. However, an AR15 with a 16" barrel sounds a lot louder to me than a 12ga. shotgun, even though charts show them to be about the same, with the AR often being maybe one decibel lower. I've also been around short barreled .223 guns that blew me away with the noise they made!
Then I came across an interesting PDF file that shows the decibel range of AR15's with barrels from 5" up to 24" and discovered that the decibel rating is nearly meaningless. It's page 14 of this file: https://ndiastorage.blob.core.usgov...0/armament/WednesdayCumberlandPhilipDater.pdf
There's only a difference of about 2.5 decibels between a 5" barrel and a 24" one, although your ears would tell you otherwise. The sound of even a 10" barrel is in no way anything like a 24". However, check out the pressure ratings in that chart. The 10" pressure is 12,400 and the 24" pressure is only 4800.
It would seem that it's the pressure in the barrel at the time the bullet leaves the muzzle that determines how loud a gun is.