I have highly corrosive sweat, and the mainspring housings of both of my hard-chromed 1911s show rust as a result.
In order to stop the rust from forming, I've resorted to a baked-on enamel coating over the hard-chromed mainspring housings.
So much for the "imperviousness" of hard chrome. But I must admit that it does a very good job of protecting the rest of the guns.
And it's not very reflective, either, since it was applied over a bead-blasted surface.

I just browsed through this thread so......

Shipwrck is correct,this ain't no auto bumper chrome,and it depends on the prep and the application,but it is better on firearms.As Steve said,it depends on you personal ph level for it to last or not.Nitrocarburizing,etc can be better,but...... I believe as Jammer said,shiney ain't really cool,but the maintanance is less and the sights jump right out at you.

As far as the original Q for customs,VA and Steve were the only hits,and Nightahwk is borderline (no offense man).Wilson,Bear,Brown are all semi-customs,and if you want to throw SA and Kimber's top shelf stuff in there I'll give you that.Custom means Heine,original Wilsons and Browns,Laughridge,Rogers,Smith,Jarvis,Marvel.and more of the old timers that escape my brain now,and some new talents like Rogers,Rodgers,Reid,Chambers.......

Think a 1911 can't do under an inch at 50yds (yes,yds)?Talk to Joe Chambers that has pulled off .8+ at 50 pretty consistantly,and built a true left hand 1911.Kimber,SA,they're a gussied up production gun,all it is.A pure custom starts about where Wilson and Brown's top of the line end for a scratch build,but it ain't the same.

Bought a Les Baer and had John Harrison make some mods. I don't know if you consider it custom, but there isn't another one quite the same. John only does full builds now so I guess I am lucky to have been able to have him work on mine.