Excluding all semi-auto rifles, .25 - .308 calibers will lose or gain 35-40fps per inch of barrel. I have one 20in 270win and one 26" 270win and the fps change with the same loads is an average of 240fps. From 0-300yds isn't enough to really worry about but at longer ranges it sure takes alot more guess work out of your shots. I prefer the longer barrels in bench shooting and hunting. For tactical and fast I prefer the shorter barrels.