My personal opinion is WD40 is not a lubricant, rust preventative or protectant, although the product is described as "WD-40 Lubricates, Cleans, Protects, Penetrates & Displaces Moisture"
I remember my armorer making me apply CLP to my M16 after he'd watched me clean it. I told him I had just sprayed it down with WD40 and he lectured me that WD40 doesn't lubricate. Well we were in Louisiana so maybe it was important, although I had to clean the damn thing once every week whether I took it out or fired it or not, and I didn't think it was going to rust in 7 days, but whatever - the armorer was doing his job.
There are lots of examples of people using motor oil on guns as a lubricant and it working fine. I think manufacturers of gun oil now have the market convinced that specialty gun oil is necessary and any other oil might be deficient.
My own experience, I cleaned my dad’s Ruger .22 with Breakfree, put it in a case with a desiccant pack and it kept for 10 years that way with no rust. It was his pistol so I mostly forgot about it and I didn’t know that he let it sit for 10 years. Time flys.
Cosmoline was a product that was commonly used on guns by the military. I’m not sure if the WWII vintage Cosmoline is the same as this stuff here – but I included the link.
http://www.cosmolinedirect.com/
http://www.cosmolinedirect.com/SampleCoatingPics.aspx?prod=Cosmoline
I know the military doesn’t use it anymore but to me, if Cosmoline worked, then packing grease will work. Cosmoline is basically packing grease with a high wax content. You hear people complaining about getting Cosmoline off, but that in itself makes me think that for rust prevention and protection it probably can’t be beat.
Some more info on it here:
http://www.theboxotruth.com/docs/edu23.htm
I decided that for my Tec-9M I was going to pack it in grease. I don’t know when I’m ever going to fire that thing again and I didn’t want to chance it to just cleaning oil. I gave it a thorough cleaning with motor oil, assembled it and used packing grease on the outside. I didn’t put any packing grease on the interior, but the outside is thoroughly greased. The thing didn’t need to be cleaned really, the last time I took it out I gave it a good cleaning with Breakfree, then a follow-up cleaning with Triflon. This time I just cleaned it with motor oil. It was more of a wipe-down than a cleaning. Then I buttered up the exterior with packing grease and wrapped that in linen. Threw a few desiccant packs in there and that’s it. The cost was about $10.00 – a quart of motor oil and a small can of packing grease.
There are lots of stories of old timers using motor oil to lube their firearms. I’m not even certain how long these specialty gun oils have been around. I’m a little paranoid about the synthetic and detergent motor oils so I got the cheapest Walmart oil I could – the all natural stuff Jed Clampett discovered when he was shootin at some food, and the thickest grade too.
