Want to set a gun shop or online outdoors forum on fire? Ask whether or not to use WD40 for guns.
The "WD" in WD40 stands for "water displacement." In simplest terms, this means WD40 can push water out of cracks and holes.
Water causes rust. Rust on the outside of guns will ruin the appearance and value. Rust inside of guns keeps parts from working smoothly or can keep them from working at all.
A second major property of WD40 useful to guns is that it penetrates. Again, in overly simple terms, it can move into tight spaces and under the rust. Parts that are frozen in place can be freed to work again by soaking in WD40. Rust can be scrubbed mostly away after soaking in WD40.
It seems like the perfect lubricant for guns, right? It lubricates, penetrates, and it combats rust. Why all of the controversy? The problem comes from a third property of WD40, it protects.
The Downside of WD40
When I was a kid, we slathered all of our guns in WD40. After a quick wipe down, we were done. It seemed to work and work well. We did not know then what we know now.
WD40 also has the ability to protect; that is, to prevent rust from forming. To do that, a chemical is left behind after cleaning to repel moisture. This chemical causes the controversy.
There are places in guns that have very tight clearances and narrow edges that engage. If never removed, this protectant continues to build up in microscopic layers. It does have the ability to become too thick and start to work against the gun's mechanics.
Like anything, there can be too much WD40 no matter how good it seems.
WD40 is a great product. Its also great for guns... when used correctly.
- Never soak your guns in anything without removing the excess, especially WD40.
- On the exterior metal parts, WD40 will do a great job.
- In the barrel, WD40 is fine.
- Avoid spraying the inner workings full of WD40 unless you plan to disassemble the whole works and clean it later.
Besides, these days there are products as good or better than WD40 specifically made for guns.
In 1971, the US Army issued Purchase Description 48 calling for a single product that cleaned, lubricated, and protected firearms. From that came a number of innovations that have come into their own in recent years. A number of manufacturers now produce highly rated CLP products or something similar. The upside is that they are made specifically for guns.
The same as WD40 for guns, if you want to stir up a message board, ask about CLP-type products. You will find those adamantly for and those adamantly against.
However, common sense dictates that these products work just as WD40 works when you use it how it is intended to use and where it is intended for use. And, as always, in moderation.