Black coating on Remington 700 bolt lugs?

[Canadian Buck]

Can someone tell me what the black coating is and used for on Rem 700 bolt face/ lug area.

Reason I ask... I have a stainless steel fluted bolt that I would like to bead blast to remove some scratches on the handel and bolt body. Must I tape off this area? Or can I blast it all off. Bolt is completely dissembled including extractor and ejector.


Thanks

Regards

 

[Blastattack]

It’s bluing. You should probably tape it off.

 

[Hitzy]

Doesn't Remington "black oxide" everything?
Or is that just another fancy word for some version of blue?