What to coat filed parts

[Blowdowner]

Hi I had to file down part of the action bar of a Mossberg SA 20. The twin Rails that carry the bolt through the channels in the receiver. What can I coat it with so it doesn't corrode and to keep it moving smoothly while adding the least amount of material. Some sort of blueing process?

 

[Ringbill27]

If you run it enough those would wear there so adding finish would probably wear again. If I understand which part you are talking about.

I’d just oil it a leave it be.

 

[packer58]

De-grease the part and hit it with some cold blue ........