If decibels are a big concern, a .45ACP carbine is going to be somewhat less loud than a 9mm carbine due to it’s lower operating pressure and velocity. Both will be quieter than when fired out of a pistol and a lot quieter than a .223. Don’t expect either to act like Thor’s hammer shooting coyotes or large dogs, though. Shot placement is still key.
Noted and agreed on that last. If I need “Thor’s Hammer” the 12 ga. shotgun (or in an extreme case the 12 ga. semi-auto - yeah, I got one after the last of these threads I posted) comes out. But, then of course I’ve thrown decibels to the wind - literally.
My .223 - yeah, that sucker is darn loud too.