You make a good point blkhwkfxr, I am just going on personal experiences, I have been using WD40 on my weapons for more years than I can remember and it has always done me well.
A light coat and if they are not used often, check them every 6 months or so and unless you live in a humid environment, you should be good to go.
Some of my milsurps have 0% bluing on them and I do not experience any trouble with rust.
As far as in the bores, I just moisten a patch with it and run it through, not heavy but enough to put a layer on the metal.
I have CLP but always seem to go back to WD40, I guess because it is what I was raised using.