Ken Waters reported that he gained around 100fps when he went from 22" to 24" with the .270 WCF. He also mentioned a letter from JOC who reported the exact same increase. My own experience with the .270 WCF also showed a 100+ fps increase when stepping up to a 24" barrel.
The Chosin Few November to December 1950, Korea. I'm not one of the Chosin Few but no more remarkable group of Americans ever existed.