I assumed the question was handguns.
About 300 yards. Not much more, tho there's a few guys around that shoot longer distances. 300 isn't impossible. We have an 18" hanging plate at a lazered 300 yards, and there's good rocks around it that are fun to shoot at.
Long barrels aren't neccesary for shooting distance. They may be easier to shoot to some degree, but mine are mostly 4" in DA's, 4 5/8 in SA's, and my ex's old G-19 seemed to work pretty well at 300. The 1911 takes a lot more sight to reach 300 than the 9mm does.
Been fooling around with one handed shooting for several years. It seems popular around here to a degree. It really makes you pay attention to the basics shooting distance with one hand. Two handed, kneeling, or sitting is much more productive, but not quite as much fun.