Will they do other coatings, such as TiCN or AlTiN?
^^ This I would be interested in knowing but I'd think the firearm would have to be stainless or carbon steel to hold up to the temps for applied coatings as they have a melting point over 1450 F NP3 is still the bees knees of resistance and wear as far as coatings go and moly resins are great too, but all in all it depends on if it's done right and impact wear as with any surface finish it will degrade quickly and rob the subsurface materials of protection via flaking and in the case of some finishes actually hold in stuff you don't want because of the surface peaks.