Quote History Quoted:
Your care routine is identical to the one I mentioned. Others say what’s on my firearm is normal. So which one is it? Normal, or poor maintenance? Poor maintenance seemed unlikely, so was the part poorly finished by whomever FN orders this screw from?
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Black oxide finish on cap screws is notorious for rusting, one of the reasons I use all stainless fasteners in my engine builds,
and the reason I've started using the black stainless cap screws on anything on my ARs (partially I'm getting lazy in my old age).
Black Oxide SS cap screwsBut they are not more prone to rust than bare steel...
Hence the maintenance thing.
What oil are you wiping the thing down with ?
You say WD-40, or you can go sit in the corner for a 15 minute time out.
Sorry, but CLP products are not that much better.
I have been using LPS-3 for going on 50 years, and also strait silicone oil.
Also, where are you storing the rifle ?
Some where cool, that warm, moist air circulates past will lead to moister accumulating, even if you can't see it.