"I've been told not to use WD40 as a lube agent"
I often get amused at the hype and slander over WD-40. Actually, it's great for what it's made for, just as other oils have special purposes so does it. Use it "right" and you won't go wrong, including on guns. Use it "wrong' and you may well regret it.
WD-40 is primarily a "water displaceing" oil. It's a modest lube and rust protector because it has a low film strength AND it drys fairly quickly to leave a gummy film. That's a lousy thing to oil sensitive trigger units with!
It is great to spray WD onto an gun that has been rained on, it will float the water up so it can be wiped off and any residual water can evaorate without danger of rust IF we follow up with dissembly and a good cleaning after the hunt.
"Gun" oils are NOT made. we are far too small a market for that. There is nothing magic in the expensive oils mixed and relabeled for gun use. Our oils are mixed from a variety of common oils. In fact, some popular gun oils have some of the same faults as WD-40! WD is is not kerosene but that's a component in it, just as it is in some other gun oils, so?
I stopped buying gun oils maybe thirty years ago, only use Automatic Transmission Fluid now. It's really good stuff for our purposes. ATF is cheap, has good film strength and leaves virtually NO residue when it finally dries. And ALL liquids, including gun oils, do evaprorate eventually.