Factory parts are hardened, but it is only a surface hardening. If you polish excessively or grind, you are removing material that is hardened, leaving soft metal exposed.
Soft metal is quite prone to wear and galling.
Xtreme line used to have DLC finish, mine has 50k on it and a lot of draws, still looks new
BUT
new Xtreme finish is pure garbage, it’s regular cerakote! Less than a 100 draws and is scratched and shows wear marks
I have ordered a spare top end, it was 6 months wait and was quite pricey. Comes with extractor and sights, nothing else.
In Canada the only place that will do it, is Freedom Ventures.