I have probably 40 kinds of lubricants on hand. I like FP-10 for match semi-auto pistols for lubrication. I saw a demo, when it first came out and its lubricating properties are impressive. I use TW 25b grease for my carry pistols. I like Eezox for a rust preventative. For a penetrating oil, Kroil, is my go to stuff. There are plenty of other good oils out there. I would never use WD-40 on any of my firearms, and I did when I was new to guns. I don't like it because it isn't a good lubricant and will solidify over time, gumming up your firearms. You live and learn. Threads like this get all kinds of different suggestions. Most of them are good.