I am not sure but I think itis the Lyman Reloading manual that did extensive comparisons of barrel lengths and velocity of popular cartridges. I was surprised at how little velocity drop there was as the barrel was shortened. I seem to remember the 06 losing 60 fps when the barrel was shortened from 24" to 20" or just 15 fps per inch. Additionally each additional inch brings diminshing returns. for instance the difference in FPS beween 20" and 21" is greater than the difference between 23" and 24". As the powder cases get larger the FPS difference doesget greater per inch, but going from 24 to 26" in a 7mm is probably only 50 fps real world. The gun manufacturers seem have it about right with the 06 at 22" and win mags and 7mm remington mags at 24" for standard barrel lengths. Weatherby istypically 2" longer than most manufacturers barrels.