Chrome vs phosphate bolts

[DG23]

Yes, a sample of one, and some research data that seems to back up the assertion . . . .

Research done on gears...

and dip-applied to all specimen external surfaces. It had thickness controllability within[0.25, 250]m([0.00001, 0.01] in). In this study, a recommended coating thickness of25 m(0.001in) was used. The specimens used for this were intentionally undersized by the coating thickness to allow for direct accommodation into the test machine with no hardware changes.This particular coating hada hardness of 63to 65 Rockwell hardness C scale (HRC)

I feel pretty good about my NiB purchase decisions when the only 'evidence' of downsides comes from a decade old study of gears. Where the NiB was 'dip applied' and none of the other specs (different thickness, different hardness, different coefficients of friction) match up with what is commonly found being used in and on carriers (and bolts) used today.

[lysander]

And, stress in steel gears if different from stress in steel bolts how exactly?

[DG23]

And, stress in steel gears if different from stress in steel bolts how exactly?

What is not different?

If you are going to test any part and the suitability of any coating that is applied to it and how the part and the coating hold up when put into service as originally designed - Should you not try to test the coating on the actual parts being considered for whatever coating?

Another way to think about it: If I had a carrier coated in NiB (inside and out) and wanted to determine how that coating held up inside the carrier where the gas rings of the bolt actually contacted those surfaces in the long term from actual use - How could I simulate that with a NiB coating (that was applied differently) done on gears and even hope to get similar results? When will those gears ever get exposed to the same gasses and left over crap from the rounds I just fired?