I just got a brand new 586-8 357 mag with a 6" barrel. I've already put the better part of 1000 rounds through it, probably half 38 and half full power 357s, all 158 grain bullets and almost all of them using hard cast lead bullets from Missouri Bullet Co.
Today while giving the gun it's first thorough cleaning I noticed a very visible scratch (possible ding from a cleaning rod) about half a centimeter long located halfway down the barrel. The scratch is almost entirely in the groove of the rifling, not affecting the land very much. I don't know what caused the scratch but it could have been from the steel base of the screw-on bronze brush I was using to clean the barrel.
I'm guessing the scratch won't affect accuracy at all since it is half way down the barrel and there's still three more inches for the bullet to go after it. Could this scratch have any significant effect on accuracy?