I bought a 20 inch barrel for my 870 express about a year ago from cabellas. I've been noticing a spot on the left rear corner of the rear sight base turning white. It looks as if something is corroding under the sight base like on a car battery. I called remington about it as they pretty much said not to worry about it. It cleans off easily with a copper brush and some oil with no evidence of it being there but it poppes back up after a couple of weeks. What could be causing this and should I be concerned.
Thanks, Flip.
Thanks, Flip.