AL, I've had 308's with 18.5, 19, 20, 22 and 24" barrels. It's one of my favorite rounds (grin).

A 22" 338 WM is a lot louder than a 308 in any of the barrel lengths I just listed. Trust me on that. The 338 burns a heck of a lot more powder and the noise from that combustion is going to go somewhere...

“Perfection is Achieved Not When There Is Nothing More to Add, But When There Is Nothing Left to Take Away” Antoine de Saint-Exupery