I have looked into this extensively and have only found one finish that will hold up to constant holster wear, weather and the wear of extensive use and that is hard chrome.
I also use only one applicator, Bob Cogan of Accurate Plating, because Bob builds and has built for decades IPSC/USPSA & IDPA competition guns. So he knows what is required and has built two race guns for me. His plating process is how my competition guns could stand up to 60,000 rounds per year. He also plates my custom rifle actions, all chrome molly done in satin hard chrome with stainless barrels.
I will tell you how hard Bob's plating is as I have seen this actually done. Cut off 3" of a plated 870 12 ga barrel, put it into a vise, squeeze it flat, hammer the jaws closed and the folds do not flake!! That is one tough finish.
Take a look here:
http://www.apwcogan.com/