I own quite a few guns, shoot a lot, clean (then lube) them every range trip.
You’ve hit on my major point: I only use a tiny amount of gun lube. I don’t need a whole lot of lube.
Even at a high usage level, the number of ounces of gun lube used in a year is very small. If a 4 oz bottle lasts me a year, then mixing up my own brew is an exercise in waste, because it’ll take me years just to try and use it all.
My other, more minor point: guns aren’t that picky. Almost any oil works for lubrication (my Garands get grease).
Where guns are picky: ingredients that can harm metal or wood finishes, or don’t do well in high heat.
So, ingredients other than plain oil, like Teflon that doesn’t do well with high heat, or things that dissolve copper (the substrate on nickel finishes) need to be carefully avoided in some cases. Commercial products carefully avoid those, or they warn you right on the label about their inclusion.
Home brews might include deleterious ingredients inadvertently. Some synthetic Gear oils harm bronze bushings and synchros, for example. So, put a bit of that gear lube (it‘s synthetic, so it must be good, right?) in your home brew, wipe down your prized nickel plated S&W and who knows what you may have done to that finish.
I’m not a chemist. I’ll leave chemistry to the guys that understand it, and experimentation to those that are willing to risk their own collections.
