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Airgun calibers and cleaning

by B.B. Pelletier

Reader JW asked for this post. Before I start, let me remind you that airguns usually do not need to be cleaned. They don’t get dirty in the same way firearms do, so cleaning is reserved for when accuracy falls off.

Here’s the question:

I was getting ready to clean the bore of my air rifle with J.B. Bore Compound but was having trouble finding a rigid cleaning rod for an air gun in .22 cal. (I’m not much on the flexible rods.) I was wondering if it would be safe to use a cleaning rod for a .22 rimfire?

What’s different about airguns? Starting with .22.
Calibers! The .22 caliber airgun is 0.218″ in diameter rather than 0.223″. When makers of cleaning equipment make bore brushes, mops and patch holders, they make them for the large (and to them more common) firearms dimensions. Fortunately, the size difference is usually too small to matter, but with custom-made cleaning equipment there can be problems. Some makers of cleaning rods get anal about bore-fit, and I have seen .22 rods that were too large to fit in a .22 airgun bore. I’ve also encountered a FEW patch holders that were too large. The makers of these tools believe that there should be as little clearance as possible between their tools and the bore in order to prevent scraping one side of the bore with the rod through careless cleaning techniques. In effect, they’re using the top of the rifling as a bore guide – but only in rimfire, as an airgun bore has far less space.

In .177 caliber, the situation is reversed. Seventeen caliber in a firearm is exactly that. Airguns are .177, which is close to .18 caliber, so they are LARGER than the firearm equivalents. This time, the problem isn’t as serious. The firearm equipment is all smaller, so the brushes don’t fit as tightly but that’s the extent of the problems.

There are far fewer .20 caliber firearms, so most folks use .22 caliber equipment if it fits. If it doesn’t, .177 can be used. Brushes can be a problem – not with finding them but with finding brushes that attach to the rod that fits the bore of your airgun.

There is LOTS of .25-caliber cleaning equipment available for firearms. And, for your information, the airgun caliber is NOT standardized. Modern .25-caliber airguns have smaller bores than vintage guns – especially those from BSA and Webley. By vintage, I’m talking about the 1950s and earlier, not the 1980s. The difference in bore size doesn’t matter as far as cleaning equipment goes – just pellets, but it’s useful to know.

I buy my cleaning rods to fit firearms and I haven’t had a problem yet. Just be cautious when buying handmade benchrest cleaning equipment.

author avatar
Tom Gaylord (B.B. Pelletier)
Tom Gaylord, also known as B.B. Pelletier, provides expert insights to airgunners all over the world on behalf of Pyramyd AIR. He has earned the title The Godfather of Airguns™ for his contributions to the industry, spending many years with AirForce Airguns and starting magazines dedicated to the sport such as Airgun Illustrated.

25 thoughts on “Airgun calibers and cleaning”

  1. Sorry for the double post and the loosely related question, but I am not sure where else to ask it 🙂

    I am going to dust off my late 80s/early 90s RWS Model 34. I haven’t shot it in over a decade. I am going to clean and oil it. I have the RWS shooters cleaning kit. I am not sure if I should both oil the main spring and the chamber. On the RWS site it says you can use a drop or two in the chamber or ALTERNATIVELY just oil the mainspring. So, what would you recommend? Also, to do the chamber…where would I want to use the needle/oil…where is the ‘compression chamber port?


  2. B.B.,

    I have read that only a nylon brush should be used for cleaning the barrel of an air gun. The reason given was that metal used on airgun barrels is softer than fire-arm barrels and is more vulnerable to scratching from brass or copper wires.

    What are your thoughts on this issue? Thanks.


  3. Jed,
    There are a few that come to my mind right off the bat and they are:1 the 17Mach2, 2 the Aguila, 3 the 17 HMR, 4 the 17 tactical, 5 the 17 Remington. They are all listed in order by slowest to fastest. Ranging from 1550fps(17Mach2) to 4225fps(17Rem). They are screamin’ little bullets. Bullet wieghts are from 17grs(17HMR, 17mach2 & 17 aguila) to 25grs(17 tactical & 17 Rem.). I hope thats answers your question.

  4. This holiday season I’m going to purchase either a talon SS in .22cal or a patriot in .25cal {if there is any left} but the main factor is sound level. Is the SS just as loud as the patriot set at one of the higher levels of power? And how much louder than my 1250 .22 is a patriot/kodiak in .25?


  5. sav300,

    are you sure you came close to an answer about the 17 calibers out there?

    Last time I counted .17HMR, .17Rem., .17Mach2, .17tact., were all the same caliber with different cases and or loads.

    Yes, screamin’ little bullets, but all the same caliber.


  6. sav300.

    I am kidding with you… that was a very good answer and you covered about all of it in that caliber.

    Kind of an interesting little projectile aye?


  7. RWS Diana 34,

    Oil the transfer port. That’s the hole in the receiver behind the barrel. You can see it when the barrel is broken open.

    The spring is probably not dry. Unless you hear a squeaking sound when you cock the gun it’s probably okay. However, it won’t hurt the gun to put a few drops through the slot in the bottom of the receiver.


  8. Hi B.B.

    Thanks for the post. It was very informative as always. I have a couple of other questions though.

    In a previous comment, a reader asked how long you could keep a springer cocked without causing any damage. If you are trying to eliminate a pest who is somewhat shy, it would obviously be an advantage to have the gun cocked and ready.

    Secondly, I am preparing to try a number of different pellets in my RWS springer. I was wondering if I needed to have any break in period before determining the best pellet.



  9. jw,

    On 10 and 11 May of this year I did a two-part posting on mainspring life. You must have missed it.

    Break in any spring gun except a TX200 for about 1,000 shots. There will be NO accuracy change, only a small to large smoothing of the powerplant, and a ferw guns will get faster. The TX is smooth out of the box, but it’s one that will speed up.


  10. B.B.

    Actually I did read your posts on May 10 and May 11. But I didn’t see an answer to the question there, at least not explicitly. I did see that after a month of being cocked, the Beeman guns lost about 5% of their power, and you go on to state: “A full MONTH of being cocked is more abuse than anyone can heap on a spring gun in ten years of normal use.” I guess the implication here is that it’s okay to leave your gun cocked for relatively short periods of time, even a few days? Sorry so dense…


  11. jw,

    It IS okay to leave a spring gun cocked for a few hours – as long as you remember to shoot or uncock it afterward! The problem would come if you put the gun away cocked and didn’t pick it up for six months.

    There is also the danger of a cocked, loaded gun being stored that way.

    I would say hours instead of days – comparing the airgun to a firearm that I would not leave loaded and cocked unless I was in a battle.


  12. I just bought a Walther CP99 the other day and the manual said that I should oil it using Crosman Pellgun oil every 250 shots. The manual also said that I should use cleaning pellets and a maintenence cylinder to clean it. I’ve been able to find the oil and cleaning pellets online, but what’s a maintenence cylinder?

    And also, to clean the barrel, do I just fire a cleaning pellet or do I have to apply something (like an oil or solvent) to the pellet before I fire it? If I have to apply something to it, would I use the pellgun oil or something else?


  13. CP99,

    You’re asking good questions. Let’s examine the facts.

    1. Airguns do not burn powder, so they don’t become dirty in the same way that firearms do. The only way an airgun gets dirty is when some of the anti-oxidant powder from the pellet is deposited in the barrel. Each new pellet removes most of what was deposited before it, so the barrel never becomes dirty beyond a certain point.

    Therefore, cleaning the barrel is unnecessary.

    However, if you want to clean the barrel, use a dry cleaning pellet. Never use petroleum oil or any solvent in a CO2 gun.

    The maintenance cylinders are fast passing from popularity, because shooters are putting Pellgunoil on the tips of each powerlet. All they were was a CO2 cylinder with a little pellgunoil or other silicone oil added.


  14. B.B.,

    Do I just put one drop on the tip of each powerlet when I put it in or should I put 2 or 3 on every 250 shots? The CP99 manual didn’t really specify when to use the maintenance cylinders, just that it should oiled every 250 shots.


  15. Hi BB

    I asked about fireing my cfx with the breech block open earlier and thanks for the quick reply and the good news. What do you think I should use to clean the outer surfaces my gun. I have a “pellet gun cleaning kit” but it has hoppes 9 in it which you said eats up seals so I just wipe it off with paper towels for now. WD-40?

    Thanks, Kyle

    • Scottyduzntno,

      Welcome to the blog.

      Seventeen caliber firearms are smaller than .177 caliber pellets. Pellets are closer to 18 caliber.

      But brushes and mops are not that specific. They will interchange. And the jag for the firearm will be smaller, if anything, so it will fit. Just watch the rod size, because a .22 rod will not work.


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