So I’ve been researching gun oils lately.
It started with gunsmith Grant Cunningham has advice on gun oils and lubricants. One of his recommendations is Dexron-type automatic transmission fluid, available for a few dollars at auto parts stores. His favorite is something that isn’t considered a gun lube at all – Lubriplate “SFL” NLGI #0 grease, which is used in the food service industry for machines that come into contact with food. I did notice he claimed poor corrosion resistance for WD-40, which did well in the some of the tests I found.
And here are those tests.
Brownell’s – Birchwood Casey Sheath, Boeshield T-9, Break-Free LP, Break-Free Weapon Wipes, Brownells Cosmoline, Brownells Rust Preventive No. 2, Hoppe’s Lubricating Oil, Rig Universal Grease, Tetra Gun Lubricant, Valvoline 5W-30, and WD-40.
6mmBR.com – FP10, Corrosion-X, Eezox, BreakFree CLP, Strike-Hold, Rem-Oil, Slip2000, Mobil-1 15W50
The Gun Zone – Kleen Bore TW25-B, Break Free CLP, Break Free LP, Shooter’s Choice Rust Prevent, Birchwood-Casey Sheath, Remington RemOil, Eezox, WD-40, Kano Kroil, 3-in-One Household Oil, Sandaro Industries’ Bore Cote, Miltec-1, Sandaro Industries’ Arms Cote
Those tests are pretty harsh. They use raw, untreated steel (or nails in The Gun Zone test) exposed to water and even saltwater. Some highlights:
Boeshield T-9 – Based on Brownell’s test I’d be inclined to use Boeshield T-9 in a saltwater environment.
Hoppe’s Lubricating Oil – Very poor rust inhibitor in the Brownell’s and Gun Zone tests.
WD40 – WD40 did well as a rust preventer, but it’s not a very good or long-lasting lubricant. Also, as WD-40 dries it leaves behind a residue, so if you use it wipe off any excess and don’t spray it inside the gun where a buildup could cause problems. That means you’ll need another product besides WD40 to use internally, in addition to a cleaning agent like Hoppes #9 solvent. It is a good thing to know if your gun gets soaked and you want something to displace the water (the WD stands for water displacement) and protect it from rust until you get home and clean it.
Breakfree CLP – Me, I use Breakfree CLP nine times out of 10. It’s a cleaner, lubricant and preservative (hence CLP) so I use it for everything: cleaning and protecting the bore, lubricating and protecting internal parts, and wiping down the outside of the gun. It’s available everywhere guns are sold, comes in several spraycan sizes or a bottle small enough to fit in my range bag, and the price is reasonable. Breakfree CLP contains Teflon particles for lubrication. According to the instructions you should shake the container before use to suspend the Teflon. CLP did very well in the tests for rust protection (though not as well in Brownell’s test, for some reason), so I don’t see any reason to buy anything else for routine use.