[flip180]

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.

[Snarlingiron]

I used to be involved in a blueing business a long time ago. On re-blue jobs, this is pretty common. It is a result of a small amount of the blueing salts being left in a crevice, such as you describe. It was pretty common to see it coming from around the barrel/action junction on rifles. If it bothers you, tap the sight out of the dovetail (if I'm understanding this correctly), clean it thoroughly with water and mild detergent, thoroughly dry, lubricate, and re-assemble. Or, just keep cleaning and soaking down with a penetrant such as Kroil, and it will eventually stop.

[Fred Fuller]

Soak it good with a light oil- RemOil, etc.- and it should stop leaching out after a few treatments.

lpl/nc

[flip180]

It's an express barrel. Will it have bluing salts as you described with it's finish. I called Cabellas, and they said to send it in for an exchange for a brand new barrel. I really don't want to do it if I don't have to.

Flip.

[Virginian]

A soaking with Ballistol will stop it is my guess. This stuff even used to be recommended to treat wounds with - no kidding.

[Snarlingiron]

The express guns are bead blasted to produce the textured finish, and then blued (or so I have been led to believe), so yes, it could have some residual salts.