I've had to keep MSDS sheets on WD-40 in the schools and in the prison system. It's mostly Stoddard Solvent (mineral spirits) with a fragrance and a tiny amount of lubricant. It cleans pretty well so I use it to loosen gunk then blow it off with air. It does raise Holy Ned with some plastics if left to sit. Applying a lubricant with solvent in it doesn't make sense. It's a good cleaner but lousy lubricant.
I had a kid set a toilet on fire with it so I know it burns pretty well.
Flash
I had a kid set a toilet on fire with it so I know it burns pretty well.
Flash
I've used this method as well. I think of it as kind of a pre-clean that works especially well for very dirty or neglected guns. I would always follow with a thorough cleaning with proper solvents and oils, I've never even considered leaving it in or just using WD40 alone.WD40 has a place in gun maintenance, but not for lub or rust prevention. I'll sometimes use it to "Blast" external parts, but that is always followed up with proper products. CLP, grease, what ever. It's also good for spying on/in wet guns, like if you're out in the rain as WD40 is excellent in displacing water. Again, followed up with other products. In a real pinch, with nothing else available, it will provide some lubrication for a short time.
Works great firing tennis balls out of PVC tubes. It'll bust the side window out of a car! or... uh... so I've heard...Squirt some in an empty plastic milk jug and then wave a lighter in front of the mouth. Or better yet, tell someone it's a cool thing to do and then stand quite a bit back and watch them do it.
WD 40 was originaly sold as a penatraiting oil for nuts and bolts and noisey door hinges.
Its not good if left in guns alone as it can work it way past primers and bullets and make
for some dead rounds when you need them.