We’re often asked what oil should be used to lubricate guns. Our response: “Oil.”
I use whatever is around. But, I clean my firearms after every range session. Long term storage, salt water air, prolonged missions, etc., aren’t major concerns in my life.
For lubrication and rust prevention, if one must have “the best“, Hornady One Shot is superior. Frog Lube is a close second. Those products offer the best all around lubrication and rust prevention in any tests I’ve seen.
However, if your life is as boring as mine, and you at least sorta kinda take care of your guns, a quart of Mobile engine oil will cost you $4 and last for decades. I have yet to have anyone show me a common firearm that has a hotter, more violent mechanical environment than the cylinder of an internal combustion engine – sure, different materials and alloys, but the principles are the same.
Since the great war, many a soldier has cleaned their gun in diesel fuel [never gasoline!] and lubed it by pulling the dipstick from an engine and dripping oil where needed. (Automatic transmission fluid is even better.) Something to remember next time you’re at the range and no one remembers to bring oil. It will work just fine and get you through the day.
Firearm lubricants, much like after market accessories, seem to be an obsession with American gun owners. And like after market firearm accessories, little of it actually applies to our lives.