We're not talking about lubricants for the Mars Rover or the Space Shuttle here. It's just oil folks. Pull some off your dipstick or out of a bottle in the garage. It will work just fine as a lube.
Breakfree/FP10/Miltec/Slip2000 etc. The all work, they all work pretty good. Try one and if works you're set. If it doesn't try something else. For me FP-10 works as the best CLP, it just seems to keep pulling out crud forever when it soaks. For lube I like Slip2000 but honestly anything sitting on the shelf works. In a SHTF situation axle grease and used engine oil will probably far exceed the needs for most modern firearms.