Well, you would lose 35fps per inch of barrel lost between 26" and 22". lets say that we had a Sendero with a 26" barrel and that with carefully developed handloads, the .300 Winchester was achieving 3230fps with 165 grain bullets and 3100fps with 180 grain bullets. By dropping 4", you stand to lose 140fps. The rsults would on average, be 3090fps with the 165 grain bullet and 2960fps with the 180 grain bullet. Its still quite powerful when you look at it that way.
Aside from the above, the bigger issues would be the increased recoil and noise. A longer barrel, especially a fatter one, has a tendency to dampen recoil immensly. Excessive noise and muzzle blast can induce a slight flinch if you use the rifle without earplugs when hunting, over succesive hunts.
There are certainly a few factors to consider. You could also get the same rifle over all length by utilizing the .300 WSM