I bought my son a Ruger American Ranch (16in barrel)for his first rifle in 556. That gun was absolutely the loudest I ever shot. On more than one occasion I had other shooters at the range inquire about the gun being so loud. For comparison I have a Ruger M77 mkII in a 243(16.5in barrel). It is loud, but not even close as to the ranch shooting 223 loads. The 243 makes more of a distinct loud shrill crack rather than a boom.
For another comparison, I own 2 Ruger M77 mkII 270’s. Both are stainless steel with boat paddle stocks. One is a standard model with a 22in barrel. The other is an ultralight model with a 20in barrel. So pretty much the exact same gun minus 2in of barrel length. I shoot the same loads in both, and yes there is a difference in muzzle blast and recoil. The shorter is noticeably louder and a little tougher on the shoulder. Where I shoot it’s covered with a tin roof. When I shoot the shorter rifle you can hear the roof panels rattle.
The quietest rifle I own is an old Ruger M77 mkI with a 26in semi bull barrel. It’s a joy to shoot and way more accurate than I can shoot it.
This is just my experience, maybe it will help.
