I checked my Ruger SRH looking from the rear or the barrel and noticed that first 1 inch or so is worned out by scratches. So much so that I can hardly see any rifling left.
I would agree with dfaris. BUT...if you actually see scratches, it begs some questions. New gun or used? Shoot alot of rounds (1,000s)? Ever get snything stuck in the barrel?
That portion of the barrel is called the "forcing cone" and it is not rifled. It is not uncommon for it to show machining marks which could appear to be scratches. It shouldn't be an inch long though--maybe a quarter to a half an inch.
It is the forcing cone that allows the bullet to enter the rifling after it jumps the space from the cylinder. If its an inch then the barrel may have had amateur "gunsmithing" get it checked by a licenced pistolsmith. Compare it to other revolvers of the same make and model.
Eyeballing it 1/4" is about right.
But cleaning the gun well after shooting lead bullets is always a good idea. When your barrel looks like a shotgun barrel and nice and shiney you really
will have to work "to get the lead out".