quote: Originally Posted by
Lanse couche couche 
At what length does length of a barrel start to have an impact on accuracy. I would assume that a .44 magnum lever action of semi-auto carbine with a 16 or 18 inch barrel is gonna be more accurate at 100 yards than a .44 magnum pistol with a 6 inch barrel.
Originally Posted by
bigcountry
Good question. Some claim one complete rotation, but I don't buy that. I know for a fact, that a snubnose will never be as accurate as a 6" barrel for 44mag.
So for a 308, with 1 in 12 barrel, I don't think you would want anything shorter than 12". Surprised, i have never read an article on it. I have read alot of articles on what is the dimenishing returns for velocity.
What you guys are referring to has more to do with sight radius with iron sights rather than the inerrant accuracy of a given barrel length.
You also have to take into account the type of firearm that the projectiles are fired from. A lever action rifle has a closed and sealed breach where as the revolver has a gap between the cylinder and the barrel where expanding gasses escape. A revolvers velocities will never be as consistent as they would be out of a sealed breach firearm and thus its accuracy will suffer.
Also take into account the burn rate of the powder. If firing from a 2" barrel the burn rate will need to be faster in order to get equally consistent velocities as you would from a longer barrel with a slower burning powder. If you were to simply fire a cartridge that was developed for use in a 16" barrel carbine out of a 2" barrel the velocity spreads would be extreme to say the least.
There are a host of other factors that will come into play but assuming that the barrel length is sufficient to completely burn the available powder, and all other factors equal, the shorter barrel should be the ore accurate barrel.