interesting, thanksI think the biggest difference between the graphite and the moly/w2s is that the graphite is a “loose” dry lube, while the moly/w2s has to be applied similar to a powder coat paint. once the solvent has dried it actually takes pretty significant force to dislodge it from the surface, usually something very aggressive like high grade fixture tape (ask me how I found that one out)
looking at the basic 620C datasheet, they certify it in presence of ice to -100F: https://everlubeproducts.com/prod/docs/tds/Everlube620CTDS.pdf
personally given the choice as an engineer, if I wanted something to keep moving without regards to fouling or very cold weather a hard chrome on the inner surface and a W2S coating on the outer would be my first choice
So for a Rifle that would be a hard chrome bolt/carrier with the interior receiver surfaces treated with 620C
as for bcg, why not a phosphate as its not as smooth so the application can take hold better? Thinking is that the chrome bcg would be more uniformly smooth and 'clean' whereas the phosphate would have catch points akin to a barrel. If anyone has ever taken degreaser/carbon cleaner to a barrel surface to strip in bare then reapplied oil etc. that's my thought here
