you are correct 4onaside. If you really want a long range rifle your talking around a 30 inch barrel.
I realize that anything beyond 26" inches becomes impractical from a handling standpoint(although I once owned a model 95 chilean mauser that had a 29" barrel, which I cut off to a more practical length). Most all of your ballistics tables use 26" barrels to arrive at their figures. I own two 26"rs, one of which I just bought for my next year's(hopefully, LOL) prarie goat hunt. However, at the ranges that most of us shoot for whitetails all of this is really immaterial, 18, 20, 26, or whatever.