Bobhouse,
Turn line?
Looks pretty normal to me.
Ruger's cylinder stop/bolt pops early and is
typical of its design in the post 1973 models.
Any amount of dry firing or shooting will start
to produce such a line.
The early engagement of the bolt allows for
fast shooting since the bolt will pop into
the cylinder notch positively. In heavy
shooting for the Colt SAA a longer
lede is cut for the cylinder notch and
heavier spring is installed for the bolt
itself. Otherwise the cylinder is apt
to fly by the notch. This plus the
SAA lockwork is totally different than
the New Blackhawk.
A turn line is also typical for Smith
DA revolvers/