We asked David Sams of Sams Custom Gunworks to answer this question submitted by a reader about the various advantages and disadvantages of different gun finishes for competitive shooting.
Q: What is the difference between stainless steel, parkerizing and bluing in terms of protecting my competitive gun? Does the gun perform differently with one of these finishes?
A: Beginning with Springfield 1903 service rifles, the military began using a more durable finish than bluing, called parkerizing. The process includes a heated bath of phosphoric acid and powdered iron and can only be used on carbon steel parts. Because the process does etch the surface of the steel, critical surfaces such as the rifling in the bore and precision fit surfaces should be protected from contact. Because of this risk, it is not a practical method of finish for a precision firearm.
Bluing of carbon and stainless steel are both a hot, caustic method of finishing firearms. Different chemicals are used for both steels, but achieve the same results. I strongly discourage bluing of stainless steel slides for use in precision builds due to the likelihood of galling between the slide and rail. One surface will “dig” into the other, inevitably seizing them together.
So, with all that said about finishes, conventional hot, caustic bluing still rules as the best rust preventative/finish to apply to firearms used in competition. There are several other finishing processes available in the world today ranging from spray-on/bake-on to plating. Both have disadvantages compared to conventional bluing. The spray-ons usually result in chipping and do add to the dimensions. Plating also adds to the dimensions and is usually in such a hardened state that it can prove to be a problem when additional work is required such as sight replacement or any further machining. As long as proper care, cleaning and lubrication is performed, conventional bluing will provide both protection and a nice appearance for many years of service.