coyota1, they do make what's called tight bore barrels in selected calibers also on custom barrels that are hand lapped you may have to cut off 1" or so at end of muzzle as that may be oversized.
I believe tight bores are less finicky than barrels with looser tolerances. This may not be the deliberate tight bore you are describing, but I know it's a positive for accuracy. I had a 700 VLS 223 that I could swear it had more constriction at the end of the barrel, although it may have been a flaw. I could feel it with a cleaning patch.
Longer barrels are more accurate, they're closer to the target.
I doubt you'll really notice the longer barrel from the bench. My SPS Varmint has one and it's only a problem in tight stands. I solved that though, I don't hunt in the tight stands any more.