Some talk about airgun lubrication: Part 1

by Tom Gaylord
Writing as B.B. Pelletier

This report covers:

  • Why do we lubricate?
  • The Meteor’s needs for lubrication
  • Leather piston seals
  • Velocity
  • Watch the performance
  • Synthetic piston seals
  • Summary
  • Other lubrication requirements

Yesterday a reader asked why I bothered with Tune in a Tube. Why didn’t I just clean the Meteor Mark I when I had it apart, lubricate with moly grease and be done with it? That tells me there are a number of readers who don’t really understand what is involved with airgun lubrication. So today I thought I would discuss it a little.

Why do we lubricate?

This is a good place to start. In fact, from the reader’s comments, it seems to be at the core of misunderstanding. Don’t we just lubricate to reduce friction?

Friction is a principal reason for lubrication. But there is more to it than that. Sometimes we want to reduce friction by a certain amount, while retaining some part of it that’s needed for proper operation. Otherwise, moly (molybdenum disulphide) would be the answer to everything. Some airgunners think it is. The reader who wrote the comment that got me started on today’s topic said that very thing — that I should just clean the Meteor’s parts and lube everything with moly and be done with it.

That would be a disaster! Let’s look at that airgun and see why.

The Meteor’s needs for lubrication

The Meteor was buzzing when it fired. Buzzing is caused by excessive tolerances that allow the powerplant parts to vibrate when the gun fires. Moly will have no affect on that. The parts may move faster than they did before when lubed by moly, but they will still bang together and vibrate in an annoying way.

What is needed is one of two things. Either the parts must be tightened in some way so there is less sloppiness or they must be surrounded by a material that causes the vibration to stop quickly. Tune in a Tube does the latter. While it does provide lubrication, the ability to stop vibration is its principal feature. Add to that the fact that it can be applied to a gun without disassembly and you have a wonderful product for a spring piston airgun. And a mediocre one for a CO2 or pneumatic gun, whose needs for lubrication are different.

I will address those other powerplants later in this series. Let’s stay with the Meteor for now. The Meteor is made as cheaply as it can be. Its piston is sheet metal that’s formed into a cylinder and welded, top and bottom. That kind of construction does not lend itself to the attachment of synthetic bearings called buttons, which are the number one way to eliminate slop for a piston . You saw me use buttons on the piston of the Diana 45 I tuned in the special 10-part series I did last year. Part 6 of that series shows most of the tricks I would normally use to tune a spring gun, but the Meteor’s thin metal construction doesn’t allow most of them. Because of that, Tune in a Tube is an ideal product for the Meteor. The intended use is a large part of selecting the correct lube.

For the Meteor piston, piston seal and mainspring I need a lube that will dampen vibration, reduce friction and also seal the compression chamber. Tune in a Tube with do the first two, and oil will seal the compression chamber. But — what kind of oil? The Meteor has a leather piston seal, so let’s discuss that first.

Leather piston seals

Leather piston seals need to be flexible to seal the compression chamber. That takes oil. Is the oil a lubricant? Yes, but in this case it’s being used for three good reasons. First, because it keeps the leather seal pliable, allowing the leather to flex and to therefore seal the air in front of it. Second, being oil, it lubricates the seal, reducing friction so the seal and the piston it’s mounted on will move as fast as possible. And third, being oil, it evaporates slowly, which means the seal will stay pliable longer. But longer than what? Well, longer than water, for example.

Water will lubricate the leather and make it pliable. A water-soaked piston seal will seal the compression chamber about as well as one soaked in oil. But water evaporates rapidly and will dry out. When it does, the leather will shrink and harden. If left that way, it will break up in small particles every time it is moved, as in firing. And, if left for long enough it will eventually dry completely, allowing the leather to deteriorate by a process we call dry rot. Oil may dry to a point, but even when appearing dry some will remain for years, preserving the leather if it isn’t worked too hard. I have seen the leather seals in airguns that were over one-hundred years old, and they were still in working condition because they had been oiled.

Velocity

The velocity of the airgun also plays a factor in the choices for lubricants. The Cardews showed in their experiments that were documented in the book, <i>The Airgun from Trigger to Target</i>,       that when a spring piston airgun approaches 600 f.p.s. muzzle velocity it starts burning some of the lubricant in the compression chamber. That is called dieseling. Like any other internal combustion engine, this burning of oils generates energy of its own. In an experiment the Cardews shot a 14.4-grain .22-caliber pellet in an HW 35 at 636 f.p.s. when the gun was properly lubricated. When the same gun was fired in a pure nitrogen atmosphere where combustion was not supported, the same pellet only shot 426 f.p.s. This proved that combustion was generating part of the energy in that airgun.

My BSA Meteor Mark I shoots light lead pellets at greater than 600 f.p.s. So it is safe to assume that it, too, is dieseling with every shot. If water was used on the leather seal, the gun couldn’t diesel and the resulting velocity would be much slower. But consider this. If I used a type of oil that combusts readily, such as one made from petroleum, the gun might go from dieseling to detonating, which means exploding with every shot.

Therefore, for guns that shoot in the high 400s to the mid-500s, like Diana 25s and 27s, I recommend a piston seal oil that’s petroleum-based, like Crosman Pellgunoil. For guns that approach 600 f.p.s. and more I recommend high-flashpoint silicone chamber oil. Now you know the answer to what oil to use in a spring gun that you suspect has a leather piston seal. It’s based on the gun’s potential velocity, and if you don’t know what that is, watch the performance of the gun after you oil the piston.

My final comment about water on leather seals — don’t do it! That was mentioned for the purpose of discussion, only. Water inside a spring gun would rapidly oxidize and cause the gun to rust.

Watch the performance

If the gun you have oiled smokes after each shot without any noise, you are using the right type of oil on the piston. It may detonate a few times at first, but two or three explosions is all you should hear. If it keeps on exploding, you used the wrong type of oil. Since the seal is leather, just wait a few months, then oil it with silicone chamber oil from then on.

Synthetic piston seals

The oil for synthetic piston seals does something different than the oil for a leather seal. A modern synthetic seal is self-lubricating, which really means that the seal material has a very low coefficient of friction. It doesn’t need oil to work its best — at least not from the standpoint of friction.

A synthetic seal uses oil as an additional air barrier between the edge of the seal and the compression chamber. Like the oil in your car’s engine, the oil in your airgun compression chamber just makes the piston seal better. Don’t use too much oil, though, because the act of firing will vaporize some of the oil and cause it to detonate inside the compression chamber.

Synthetic seals come in all modern airguns, but since most of them shoot faster than 600 f.p.s., I advise everyone to use silicone chamber oil for their seals. It saves me having to explain all that is in this report, every time I talk to a new airgunner.

Summary

Today we have discussed lubricants used for two purposes. The first is to reduce vibration between moving parts in a spring-piston powerplant. And the second is to lubricate the piston seal.

When it comes to the piston seal we discussed the three purposes for oiling leather piston seals, and what types of oils work best. We learned that it depends on the power the gun produces. We also discussed what lubrication does for synthetic seals, and how that differs from the needs of leather piston seals.

I held nothing back today. If this report put you to sleep, my advice is to have someone else tune your spring guns. And, I’m just getting started. There are other lubrication requirements that deserve a thorough presentation as well.

Other lubrication requirements

Sealing pneumatic and gas reservoirs and valves
Reducing friction on metal parts
…heavy wearing parts like linkages
…triggers
…piston bodies and spring guides
Oiling pellets

As you can see, there is a lot to lubricating airguns, and I plan to tell it all.

43 thoughts on “Some talk about airgun lubrication: Part 1

  1. A spring, if straight, doesn’t necessarily need to vibrate whilst decompressing, at least not in pure physical terms, if its preload is just so and it is allowed a small amount of rotation, a good tuner will know enough to engineer out the buzz as far as possible before lubrication is even thought of, in reality though getting the preload just so robs a certain amount of power. The best airgun tuners in the UK are surprisingly sparing with grease.
    Going heavy with grease and putting tight fitting guides are a belt and braces method and create their own frictions…though a lot easier for the amateur to acheive
    If you look inside a Walther LGV or an AA TX 200 you won’t find the gloop and hammered in guides, yet they are notably smooth shooters…and that is the nirvana.
    Cardews tests were carried out when leather seals were the norm, which always diesel when oiled correctly..a modern parachute seal, after a few hundred shots won’t be dieselling at all…and that includes the HW35, there is no propellant left to burn, Weihrauch recognised this subtle difference between how the leather and PTFE seals made power and reduced the transfer port size on the rifles that changed from one to the other…if you convert a HW 35 to a PTFE seal, you will experience s loss in power (and one of mine does, I have two, one with PTFe and smaller TP and one with a conversion and larger TP, the difference is neatly 2fpe when it was less than 1 before the conversion)


    • Dom,

      Thank you for your most excellent insight. As you have pointed out, the vibration and such can be designed out, but as you also pointed out such reduces power and that is the rub so to speak. So many are in pursuit of the uber magnum sproinger that produces astronomical velocities and power. It is only after they shoot such that they come to realize they have a half wild cantankerous mule in there hands.

      That is where the aftermarket tuning comes to play. Most will still want the massive power, but would at least like to eliminate the “grinding” and vibration. As BB has shown, if applied properly a dampening lubricant can reduce or eliminate this and not reduce power very much.

      This is why I have such high praises for Tune In A Tube. If you know your sproinger does not have other issues such as damaged seals, broken spring, etc., this is an excellent product for the average airgunner to use themselves without having to find a tuner who more often than not will do just about the same thing.

      I picked up an uber magnum sproinger myself recently. In the future it will have the spring changed out and possibly bearings, bushings, etc. inserted into the power plant, but for now a little grease makes it usable.


    • Dom,

      I learned about black tar and nailed on spring guides from Ivan Hancock and his Mag 80 Laza kit that I installed in my R1. He was tuning an action (HW80) that hadn’t been designed from the ground up to not vibrate.

      On the other hand, the TX200 is designed right to begin with and doesn’t meed those fixes. And ironically, it copies Hancock’s Venom Mach II.

      I agree that if the gun is designed to not vibrate from the start, a lot of the tricks are not necessary. But if not, then many of them are.

      B.B.


      • B.B.,

        I asked a question in Part 4 of the Meteor Mark I report about a bought new air rifle that is “a bit creaky when it is cocked and both vibrates and twangs when it is shot.” The rifle is my barely used Walther LGV Ultra. It is several years old now, as it is simply harsh and unpleasant to shoot. It sits in the “bad shooters” corner of my basement. My hope is that Tune-in-a-Tube will make it meet the esteemed reputation of that model, but I wonder.

        Yesterday I picked it up and shot it a dozen times and found that it is not quite as creaky to cock as I remembered, although it still vibrates and twangs like a banjo. But would Umarex ship a bone dry air rifle? If it was defective (a la a kinked spring), wouldn’t Umarex’ QC have caught it?

        Michael


  2. B.B.,

    Nice comment,…. and it vaporized. In short, that 636 vs 426 is huge to attribute purely to dieseling. Good test though.

    It also begs the question, what is the effect of that oil at shot 20 vs 500? Drying, vaporization, etc. That remaining thin film will continue to be responsible for (maintaining) that 210 fps increase? Very interesting.

    Chris



      • Wow, that’s pretty cool; I look forward to next installment. I have a question or two now, but I’ll wait to ask since the answers are likely already forthcoming. As always, keep up the good work! 🙂


    • Those numbers say that around 55% of the energy (in the faster case) comes from dieseling. Since the molecular weight of air is actually higher than that of pure nitrogen that does not explain any part of the difference either. What else could there be at play or are fast airguns actually firearms?



        • Your take would be a fact, but that’s beside my point. Spring air guns are supposed to take the energy to launch the projectile (pellet) from the compressed mainspring. If over half of that energy in fact comes from combustion instead, it won’t be hard for a federal attorney to argue that that is in fact a firearm. Thus all the same legislation that applies to say 10/22, AR-15 or Barrett would apply to your air gun.

          That’s why I want to learn if there might be anything else in the test setup that might explain part of the difference. It doesn’t need to be a big thing to push the combustion back below the 50% point. I probably have no other option than to hunt down the book and check for myself.


          • Monophonic,

            Yes, I had/have a hard time believing that this concept would continue to occur over many, many shots. I tuned a TX 200 and it detonated on the first shot. I think it shoots in the 600 fps range and the fact that it detonated would indicate something in the 1150 fps range,…. so the concept has merit. I just can not believe that it last. B.B. said that he would comment more on that in the future,…. so I just left it there for now.

            Good luck on finding something on the topic. Keep us posted.



  3. This is very timely for me. I recently got an HW35 that was the filthiest inside I’ve ever seen any gun. After de-griming it, I kept finding different advice on what to use for lube on the leather piston seal. Everything from silicone oil to neatsfoot oil.


  4. Looking forward to the rest of this blog B.B.!

    I have a whole collection of different types of moly grease ranging from creamy-smooth to thick and sticky. The grease I chose depends on the rifle (vibration/tolerances) what I am trying to accomplish – I am very interested to read your lubrication suggestions.

    I was told (way back when) that the moly bonds directly to the (clean) metal and becomes the interface to the lubricant (grease or oil) . So instead of metal/oil/metal you end up with metal/moly/oil/moly/metal which greatly reduces friction and wear. I was cautioned not to use moly until the metal parts had had a chance to “wear in” and lap themselves smooth. I have seen rifles that were molyed when new and they never performed as well or were as smooth as ones that been broken in before a moly tune was applied.

    For years I used an oil/STP mixture for compression chambers on the 350-600 fps springers we had then. Wonder if anybody else used this brew, it worked well with leather seals.

    Hank



  5. BB

    Thanks for opening my eyes about the different tasks for lubrication. I bought Tune-In-A-Tube for my metal springers. Am looking forward to your future comments on its mediocre uses for air springers, single pnuematics, multi pump pnuematics and dark side pnuematics. I tend to follow the manufacturer’s direction for lubing synthetic seals but wonder about the need for brand products. Will be good to get your advice on best lubes for stress points like linkages. Aside from internal lube needs, I have found that silicone cloth is an excellent rust preventive for both air and firearms. It also works well on wood stocks. There is no mess and finger prints are wiped away. Am I missing something? Maybe others have moved over to the clean side also.

    This is one of your best!

    Decksniper


  6. I was sort of hoping that Ballistol would do all the necessary lubrication. 🙂 Is there any particular thing that it does not do?

    I hope all blog readers and everyone else is safe from Hurricane Matthew. I just heard from a friend who had to evacuate within 24 hours. Where do you go? What do you do? I’m sure there is not enough shelter space for everyone. I guess the expectation is that people will find friends and relatives. Otherwise, keep driving. I’m sure the motels are completely filled. Here’s a great reason to keep a bugout bag.

    Matt61



    • Matt61,

      I have also been using Ballistol ever since reading about it here from B.B.

      I put it on almost everything as a protectant, especially metal, wood, and Bakelite. It does provide some lubrication. Every time I use it things move a bit more smoothly. But if I really want to lubricate something, from now on I’m thinking I’ll get Tune-in-a-Lube (grippy) for springs, Moly (slippery) for action parts, and a small dab of silicone lube (high flashpoint) for seals.

      Oh, and 3 in 1 for household stuff!

      Michael


  7. Years ago, on the IWA gun show, I saw a match airgun maker (I think it was Feinwerkbau) exhibiting target air soft guns. Goal was to circumvent age restrictions in the German airgun law. A handgun and a rifle, they shot big round plastic balls (I think about 9mm) and used the same precompressed air system as their normal older match guns, only with very tiny air pump tubes. I never saw these again, guess they could not compete against the laser systems.


  8. Mr B.B.
    I have read your introduction to this thread.
    I never said such. You take literary license to a new level and do me a discourtesy by statements in your introductory statement.
    My challenge to you was not the use of Tune in a Tube, as you should well know.
    It was your method, and in doing such the lesson that novice or those lacking knowledge in mechanical fields might well learn.
    However if your interpretation or the slant you wish to adopt is such, there is not much I can do about it, except invite you to please reread my input and think on.
    /blog/2016/09/bsa-meteor-mark-i-part-3/


  9. In regard to protection of action and wood.
    I have found unadulted beeswax to be superior to most. Here are a few reasons.
    It stays put. It doesn’t run, a simple wipe over with a cloth is all that is required, although not necessary every time.
    It does not allow acids from handling to reach the metal.
    It prevents oxidation/corrosion at the action/stock interface
    It does not contaminate the woodwork as oil does over time.
    It is a well proven, honest product. not a over hyped or over priced.


  10. Graphite?

    Discussion please, about the appropriateness(or not) of graphite for any airgun use?

    This question is prompted by the claim on a just recently purchased tube of Panef powdered graphite lubricant, which says “Powdered graphite is the finest lubricant for metal, wood, plaster, and rubber.”
    ( If we substitute “plastic” for plaster (plaster??), we have many air gun parts. )

    Second question: How, when, where, why, would anyone lubricate plaster?

    Thanks for responses!


    • CBS,

      I think you have already answered all of your questions. Plastic for plaster! That’s rich. I was trying to think of something clever to say, but I think you nailed it.

      No one lubricant works for all situations. That blows the claim up right there. Depending on what you want to do graphite might be the best, is the way to say it.

      B.B.


  11. Hi BB, my springer buzz (or more of a twang) during firing, but only for some pellets and not others. It’s quite broken in, I think, with a couple 1000 pellets and I lube it according to the recommended schedule. The buzz never seem to go away. What is causing that?

    Regards,
    Peter



  12. Nice article. I find that my Stoeger X20 S rarely needs any oil, but I live in the desert and the worst enemy of any gun is moisture. Lubricants offer a great moisture barrier. Here, moisture is rare and I’d be nervous about any grease that might pick up the ever present dust and bind the action. I use a few drops of synthetic oil maybe every month or so on the charging lever linkage joints, on the trigger assembly and a drop around where the safety slides in and out of the rear of the upper.

    As a test, I put a drop of oil on each of a half dozen pellets and fired them to see if anything would change and to add a little lube to the barrel. No difference other than a little cloud of spray that accompanied each shot.

    After the initial break in (I’ve probably put 4-5000 lead pellets of various types and weights through it) my velocities seem to have stabilized and accuracy (which right out of the box grouped at 40 yards inside a nickle) is constant at 40 yard groups within a dime from a supported position. Most of that is due to the excellent scope that comes mounted and bore sighted from the factory with the rifle.


  13. I just tuned an old .177 Wischo BSF 55N (circa 1972 ARH) using both the traditional lubes and then Krytox. I first did the original “leather” and the legacy lubing tecniques (heavy and clear tar, moly, etc). I found a synthetic O-ring for the breech seal, perhaps the biggest improvement in this whole project!. I got good velocity (750 fps with HN match) and consistency (SD 800 fps, SD <5, and gave the most crisp firing behavior I've ever seen in this gun. Now the challenge is the horrible 55N scope ramp, which is about as snug as a bungee cord! I might need a gunsmith with the proper taps/dies/skill to fix that: the receiver is thin so there's a limit to the "threadcount" you can use to really tighten it down. Even worse, the ramp contour is different from the rifle tube, so it might take some "bedding" epixy too…

    Earlier, I did the same tune on my F124,but without a piston sleeve. It also improved velocity and accuracy but it still "twangs" a bit. So I may sleeve that one as well!


  14. I just tuned my vintage .177 Wischo BSF 55N (circa 1972 from Robert Law’s ARH), first using both the traditional lubes and ultimately, DuPont Krytox. I used the same new spring in each build. In the first rebuild, I installed a fresh leather piston seal soaked in silicone 50wt shock oil, and the Maccari ARH lubes (heavy and clear tar, moly, etc). I found a synthetic O-ring for the breech seal, perhaps the biggest improvement in this whole project!. I got good velocity (750 fps with HN match) and consistency (SD<10). However there was still dieseling with a bit of "twang". So it stripped it down again, degreased everything to bare metal with cleaning fluid and isopropyl alcohol, and installed a Vortek 26mm synthetic seal kit. I also made a piston sleeve out of PET from an Icie bottle. Before assembly I carefully lubed everything with Krytox 205 by moistening all surfaces with a nitrile-gloved hand. Upon shooting, I got no dieseling, a very nice firing cycle (no more twang!) and a mv of 830 fps, SD <5. Best of all is the sought-after crisp firing behavior never seen in this gun. Time will tell if it holds up, as I did no special honing or anything to the 40-yr-old compression chamber. I don't know if the seal, sleeve, or Krytox did the trick, or if it was the combination of the three.

    Now the challenge is the horrible 55N scope ramp, which is about as snug as a bungee cord! I might need a gunsmith with the proper taps/dies/skill to fix that: the receiver is thin so there's a limit to the "thread count" you can use to really tighten it down. Even worse, the ramp contour is different from the rifle tube, so it might take some "bedding" epoxy too…

    So far I have invested more in parts and lubes than on the original $89.50 purchase ! (not corrected for inflation so that's not completely true!).

    Earlier, I did the same tune on my F124, using Krytox, a new spring and seal, but no piston sleeve. It also improved velocity and accuracy but it still "twangs" a bit. So I may sleeve that one as well!

    Moderator, if you decide to keep this post, feel free to move or add it to your 55N 3-part story, which along with the many Krytox posts on GTA, was the inspiration for this project!


  15. What is lube in a tube (chemically) and where can i get it? I’m was trying to go “petro-less” and “moly-less” with Krytox to get rid of dieseling and it seemed to work. I get good reproducible velocity that way. But I appreciate that velocity isn’t the whole story: metal wear is also important. I just like the idea that filling your gun with gobs of greases might not be necessary. I don’t know how I missed “lube in a tube” with all the reading i’ve been doing here and on GTA! So I searched “lube in a tube” there and came up empty! so im anxious to learn more about it.


  16. Thanks BB and tt, i actually did search that…interesting material, I’m still left with no clue as to its composition. In the meantime, I’ll use the expensive Krytox i already bought!


    • Ljc300,

      If you are going “petro-less” and “moly-less” with Krytox then Tune in a Tube is not the product for you. The product dampens the springs which are not fitted to tight tolerances without the hassle of disassembling the spring piston. Since you are already fitting piston sleeves to tighten the tolerance this will do the same job without the addition of grease.

      From what I have read of Krytox there are varieties that have moly in them.

      Siraniko


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