by Tom Gaylord
Writing as B.B. Pelletier

This report covers:

  • WD40
  • WD40 as penetrating oil?
  • Not for clocks!
  • Air Rifle Headquarters
  • Light oils
  • Use for airguns
  • Special purpose weapons-grade oil
  • Household oil
  • Special purpose oils
  • Ballistol
  • Silicone lubricating oils
  • Silicone chamber oil
  • Crosman Pellgunoil
  • Summary

Okay — today is a report several of you readers asked for — some common sense talk about which oils to use on airguns, and where. It has to be common sense because I am not a petroleum engineer. I’m just a guy like you who has used a lot of oils over my 73+ years. And I will start with the one that started the discussion.

WD40

WD40 was created in 1953 by a small aerospace engineering firm called Rocket Chemical Company. They were looking for a formula to displace water for the aerospace industry. On their 40th attempt they succeeded and called the product WD40.

Aerospace contractor Convair first used WD40 to protect the outer skin of the Atlas missile from rust and corrosion. It worked so well that some employees sneaked some cans out of the plant to use at home. A few years later, Rocket Chemical founder Norm Larsen put WD40 into aerosol cans, to see if the public would find uses for it. It hit the shelves in San Diego, Rocket Chemical’s home, in 1958.

My own introduction to the stuff came around 1965, when my stepfather showed me how to dry the points of a car that had stopped running after splashing through a high puddle. But a few years later I was spraying all the firearms on my tables at gun shows because the stuff smells so nice. The purpose was to prevent rust, which the product does, and when you wipe it off, all the fingerprints and spots come off the blued finish.

My use for that purpose came to a screeching halt in December of 1977 when I returned from Germany and retrieved the guns that I had left with my parents. I had sprayed all of them with WD-40 when I left them there in 1974 and they were now covered with a yellow varnish that was so hard I had to pound on the bolt of my bolt-action rifle  with a plastic hammer to get the action open! It took me months of cleaning to get that varnish off all the guns and WD40 was what I used. The solvent vehicle is naphtha (its hidden as a petroleum distillate in the US product contents but specifically called out in Australia) and it works wonders to dissolve the dried product.

WD40 as penetrating oil?

I see on some of the British car shows on TV that WD40 is used as a penetrating oil, and I can’t deny that it does work that way. I never used it that way myself, but that was probably more because I was a gun guy rather than a gearhead.

I no longer use it on guns like I did in the 1970s, but like many households there is a can or two around. Yes, it will quiet a squeaky door hinge, but less than a year later the squeak will be back. A shot of silicone lubricating oil lasts for a decade easily.

Not for clocks!

I attended an horological (clock and watch repairman, as well as those just interested in the measurement of time) club’s meetings for about 6 months in the early 1990s — thinking that I might take up horology as a hobby. That was until I discovered that the tools a horologist needs costs thousands to acquire and the knowledge takes years to learn! I was about 44 years old and was the youngest guy at the meetings by several decades. 

One meeting we had was all about oils for clocks and watches. When WD40 was mentioned everybody went into low earth orbit and they all had horror stories that were pretty much the same as my gun story from years before.

I have no recommended applications of WD40 for airguns. If you do use it, remember what I said about it drying and leaving a varnish residue.

Air Rifle Headquarters

Yes, Air Rifle Headquarters did recommend WD40 for displacing water and preventing rust, which it was formulated to do. But they also called it a multi-purpose lubricant, which is was not and still is not today. ARH also recommended a lubricant called Dri Slide that was moly particles suspended in a volatile petroleum distillate (naphtha) base. I used Dri Slide a couple times until realizing they every piece of uncoated steel I used it on developed rust within a week! Dri Slide is still being made and sold today and no doubt it has applications but I’m warning you not to put it on steel parts that are in the white (uncoated). You must remember, Air Rifle Headquarters wrote their catalogs in the 1970s, when less was known about many things.

Shop Benjamin Rifles

Light oils

Okay — got that out of the way. Now let’s talk about some oils you can use on airguns and why you would choose to do so. I’ll begin with light oils. Like I said, I’m no petroleum engineer, so I’m just going to talk about this like I would if you were standing right here beside me. There are lots of light oils, and by “light” what I mean is oils with low viscosity. I suppose penetrating oil qualifies, but I would like to address it separately. What I’m talking about now are light lubricating oils.

I’ll start with your wife’s sewing machine. If it’s a good one and if she knows how to care for it, she has a bottle of very lightweight oil. It’s white mineral oil. Every so often, based on the amount of use or the time that has lapsed, she oils several places on the machine and then runs the motor wide open to spread the oil. It doesn’t collect on the parts and gears like WD40 does.

Another light oil is clock oil. Most of it these days is synthetic and is very low in viscosity to penetrate between the jeweled bearings or just the brass plates and the steel pinions that turn in them. This oil comes in grades that are formulated specifically for wall clocks and grandfather/grandmother clocks.

Skateboard oil is yet another light oil for the bearings of skateboards and roller blades. It is thicker than clock oil and sewing machine oil. It has superior wearing capability despite the lower viscosity.

Use for airguns

Use light oil sparingly for an airgun. Most of it won’t stand up to the heavy wear it needs to, but on things like triggers, beartraps, some detents and things like that, it is okay. If the detent will see heavy use, like a breech locking detent, I wouldn’t use light oil.

Special purpose weapons-grade oil

These oils didn’t really exist when I was a kid. I think LSA (lubricant, small arms) was my first encounter. And by the way, this stuff is also called lubricant, semifluid, automatic (weapons) and lubricating oil, semifluid. When I was in the Army we all carried a small plastic bottle of it for our M16s, and, if used correctly and in the right amounts (which is more than most soldiers think), it works well.

Other weapons-grade lubricants are mostly a mystery to me, but I did use EWG (Extreme Weapons Grease) in place of Tune in an Tube to quiet the mainspring and cocking link of a Diana model 50 spring-piston air rifle. It worked great and the spring was quiet. This report isn’t about greases, so that’s all I will say, except to note that if an oil says it is specially formulated for weapons, it probably is and should be worth a try. I would use special purpose weapons-grade oils according to the directions on their label.

Household oil

When I write “household oil” for this blog I’m thinking of 3-IN-ONE oil. But it doesn’t have to be just that. I’m sure there are hundreds of household (general purpose) oils around the world that are all pretty close or identical. By sheer coincidence, WD40 purchased 3-IN-ONE oil in 1995, so there you go!

For the past 50 years I have used a can of PL-S Lube Oil, General Purpose as my household oil. As far as I’m concerned it’s the same as 3-IN-ONE, though I’m sure there are experts who know different. But I use it for the same purposes and yes, I also own a can of 3-IN-ONE.

I probably got this one when I was in the Army, or I bought it at a gun show. I use it for all general lubrication, and on airguns that includes lubing the cocking linkage and the pivot bearings (in the action forks of a springer), and any general purpose application there might be. I use it when I need to lubricate without disassembly. It’s a little too viscous for use on triggers that are more complex than the direct-sear types that you find on American multi-pumps. For them I recommend light oil or special purpose greases such as moly paste.

Army oil
I have used this can of general purpose oil for the past half-century.

Use household oil on airguns in the same way you would use it on other things around your house. Just remember, a PCP trigger mechanism is far more complex and not as robust as a door hinge, so keep the household oil use to high-stress parts.

Special purpose oils

Most of you will not have heard of assembly oil, but those who work on complex  mechanisms might have. Like assembly grease only lighter, assembly oil is tacky — to hold those bothersome little parts in place as they are put together. Two good uses on airguns are those teeny tiny ball bearings and super-light coiled springs. After assembly you don’t want heavier grease to impair their function, so assembly oil could do the trick.

assembly oil
This bottle of assembly oil from Dennis Quackenbush has lasted me more than a decade.

Now, what about penetrating oil? Well, WD40 may work well, but I have found that oils that are blended specifically for penetrating work the best. I use Kroil because when I did an internet search it was the product that kept coming up. It’s not the only brand — I used Liquid Wrench for many years. And lots of people swear by PB Blaster. 

Kroil
Kroil is one of several penetrating oils.

Use penetrating oil as intended. In other words, use it to free stuck fasteners. It’s not a lubricant, strictly speaking, except in a very narrow and limited way. If you need a thin oil, use either one of the light oils I mentioned, or perhaps a weapons-grade lubricant that is also light.

I mentioned oiling the mainspring of the Winchester 422 in Part 2 of that report and I told you I used Snake Oil. Snake Oil is the sort of special purpose oil I’m now referring to. I used it because the 422/Diana 22 is a very low-powered pellet rifle and I didn’t want to hamper its performance in any way. But the mainspring, spring guide and piston were all dry and I wanted to get something on them just to keep them from galling. When steel rides against steel without lubrication it wears the parts away. That’s galling. Any oil in that case is better than nothing.

Ballistol

Ballistol is probably close to a special-purpose weapons-grade oil but it is used almost universally. Besides being good for lubrication it is a superior rust preventive. Many armies around the world use it for their fully automatic weapons. However, where WD40 smells nice, Ballistol smells like a fish market!

Silicone lubricating oils

Now comes a question that people have asked me for many years. Can they use silicone lubricating oils on their airguns? They obviously have a can of the stuff that they use on door hinges and will it be okay on their airguns? Well some will and some won’t. Silicone lubricant is a class of lubricants that spans too wide a spectrum for me to make specific statements. I have a couple cans of it, too and I use it mostly on the many hinge joints of my segmented garage door. For that purpose it works great and it lasts a long time. On airguns, though, I would like to see something more specific and something with a higher viscosity.

Silicone chamber oil

And this is where we get into a lot of trouble with silicone lubricants. Silicone chamber oil has almost no viscosity and will not protect metal parts from galling. But it does have two redeeming features. It seals synthetic piston seals well and it has a high temperature flashpoint. In other words, it doesn’t burst into flame or explode easily. It’s ideal for lubricating spring-piston airguns that have synthetic piston seals. And that’s about all it’s good for on airguns. Use petroleum-based oils on all leather seals exceopt those that are pushing the boundaries of performance, such as the Diana 45.

Oh, some companies recommend silicone chamber oil on the tips of new CO2 cartridges, but only because they don’t have another product to recommend, and they sure aren’t going to recommend a product made by their competitor. Which brings me to today’s final oil.

Crosman Pellgunoil

Crosman Pellgunoil is a blend of non-detergent motor oil and an o-ring preservative. Its number one use is for sealing each new CO2 cartridge before it is pierced, so the oil gets blown into and around the inside of a CO2 gun powerplant to get on all the internal seals. I can’t recommend it highly enough, because it preserves CO2 guns for a very long time.

Pellgunoil
I use the oil Dennis Quackenbush formulates that’s equivalent to Crosman Pellgunoil.

I keep a bottle of Pellgunoil out all the time. I use it for CO2 cartridges and also for the linkage pivots on multi-pump linkages, as well as on their pump cup heads. Besides the bottle I have a pint of the same stuff in reserve what I hope is a lifetime supply.

Summary

Well, that’s my report on lubricating oils and their uses on airguns. As you can see I didn’t tell you specifically which oil to use on the inner cocking link of a Diana 48 sidelever. That’s for you to decide. But, after reading my report, I hope you won’t use silicone chamber oil, Dri Slide or WD40. Household oil would be okay and there might be a special-purpose weapons-grade oil that would be even better.