Home Blog  
Education / Training How to find airgun leaks & what you can do about them

How to find airgun leaks & what you can do about them

By B.B. Pelletier

How do you find a leak in an airgun? What do you look for? For that matter, WHERE do you look? We’ve talked about O-rings, seals and how Pellgunoil miraculously seals a gas gun. But I never told you how to find the leak in the first place! Now’s the time!

I’m forever blowing bubbles…
…and so are pneumatic and gas guns that leak! Soapy water is the traditional way to find air leaks. Airgun repair shops keep a soapy solution around for this very purpose, and you can use the same method. Get some dishwashing liquid, mix it with a little water in a small drinking glass, apply the soapy solution to the places on your gun suspected of leaking. If there’s a leak, you’ll see bubbles forming in the soapy solution!

What if the leak is deep inside the gun?
Not all leaks are found by the first method, so there’s another way to detect leaks that are deeper in the gun. Wipe a film of soapy solution across the muzzle of your gun with your finger. If the valve is leaking at the exhaust side, your muzzle will blow bubbles.

In a hurry & no time for soap? Try this!
If you’re in a hurry, here’s a fast way to find leaks: stick the muzzle in a basin of water. If it blows bubbles, the valve leaks. I’ve used a toilet bowl in a pinch (for testing airguns, of course!). Remember, you are putting only the muzzle in basin of water – not the whole gun or even the entire barrel!

Do NOT leave water on your gun
Guns and water don’t mix well, so make sure you dry the gun completely after any of these tests. I don’t think a towel will do a good enough job, so I suggest that you use an air hose or some other kind of forced air. Dry-firing the gun several times is a good way to dry any water that’s in the barrel. After you’re sure it’s dry, wipe down the gun with a good oil. If it’s a CO2 gun, shooting a Crosman Pellgunoil CO2 cartridge through the gun would not only be the perfect way to finish the after-testing maintenance, it might even seal the leak!

Sometimes, you can hear the leak!
Sometimes you can hear where a gun is leaking if it’s a fast leak. You need to be in a quiet place, plus it helps to cup your hand around the gun parts you suspect of leaking. If the leak is fast, this is a quick way to pin it down.

What about sloooooooow leaks?
There are leaks so slow they are next to impossible to find in the traditional way. Like magnesium car wheels that become porous after driving on salted streets, there are airgun leaks that may never be found. You have to be reasonable. Most of my airguns hold their charge for years, but I have a vintage Crosman pump that loses its one-stroke maintenance charge in two weeks. The solution has been to pump it twice when I want to leave it a long time, and to check it every six months. So far, that’s worked. Don’t throw the baby out with the bathwater!

Let me know how you find leaks!

160 thoughts on “How to find airgun leaks & what you can do about them”

  1. What you have is called a fast leak. Have you tried using pellgunoil yet? It can sometimes fix a fast leak, too.

    You migh try a Crosman maintenance kit, which is essentially a powerlet with oil inside.

    The point is to shoot the gun while it is leaking so the oil gets blown through the entire valve and coats all the seals.

    Tell me what you’ve done already and where your gun leaks (read the posting again) and we’ll see what more can be done, if anything.


  2. well thanks fopr the tips, I finally got it under control. I did’nt use the Crosman oil, I used an oil for singer sewing machines. I’m amazed that it does’nt fast leak anymore. I’m still looking in to see if there is still any little leaks. Thanks!

  3. This is a stupid question but I am new at this. I bought a Crossman CO2 pistol and it is great. I fired off about 8 test shots and then when I went to put the gun away, I unloaded it and took out the CO2 cartridge, which never worked again.

    My question: Can I leave a CO2 cartridge in even if I don’t use the gun often and keep it in a case in a closet? It seems a waste to fire a few shots and then lose the whole cartridge. What is the best way to store a gun like this and still make the best and safest use of the various components?

  4. Sorry – my model is a Crosman 1008B. Cannot find anything in the manual that says if it is safe to leave the cartridge in or not. And if it is safe, what is the highest indoor room temp the gun can stay in and not have problems?

  5. Alice,

    You can leave the CO2 powerlet in some guns for years without damage or danger. I am testing a Crosman 2240 pistol right now and I’ve left it charged with the same powerlet for three months. I have other Crosman guns in my collection that have remained charged for several years. I once bought a Crosman model 111 pistol that had kept its charge for about 20 years.

    The only guns where leaving a powerlet installed is not recommended say so in the owners manual. There are a few whose design is more fragile and they can develop problems if left charged. If there is no warning in the owner’s manual of your pistol, I would say go ahead and leave it.


  6. Thank you SO much. Great website and information.

    One last question. I live in a city but have a small backyward that is overrun by racoons. The city won’t trap and take them away and I can’t go outside with a shotgun either without scaring the whole enighborhood. Would a pellet gun deter or actually kill and/or seriously injure a racoon? I want to scare them off but don’t want injured and angry racoons lying around the yard. What about plastic BBs?

  7. Alice,

    You know, I don’t have any experience in deterring raccoons. Pellet guns will kill tham humanely, but that doesn’t sound like what you want to do. My brother-in-law trapped six of them in a Have-A-Heart trap and drove each one about 20 miles before releasing it. That sounds like a lot of work to me.

    Also, please be careful! Raccoons are prime carriers of rabies!

    Maybe one of our readers has a little more experience than me. Have you spoken to your county or state wildlife services office about this?


  8. Hi, its a crossman 357 – 6 shot revolver, I recently purchased it- was told it was in good working condition, instead of taking it back to the guy i bought it from, i was sure I could fix it, but as I was removing parts the charged gas cylinder blew a few parts away, including the tubing.
    Now when you place a fresh cylinder into the gun, it empties in a few seconds as the tubes are not sealed.

  9. Gamo 1250,

    Get a good set of rings with the scope stop pin built in. The recoil from a Gamo 1250 isn’t strong enough to bend a scope stop pin unless it was made from unhardened steel. I suspect you were using inexpensive (Gamo?) rings. They won’t take that kind of stress.

    B-Square or AirForce rings will be strong enough for your gun.


  10. I have thought about taking it into the shop but my other half is already upset about spending $ on what is now a pile of parts.
    I have all the parts and know where they go, but just need the tubes etc sealed.

  11. When I put the co2 canister into my gun, it leaks and sprays everywhere and is empty in about 5 seconds. Is there supposed to be a rubber washer or a seal? I’m trying to fix it for a friend. It’s a Crosman 357 air pistol. Might the oil work for it too?

  12. 357 fixer,

    It sounds like you are missing the seal that the powerlet butts against. It’s a thin synthetic seal. I don’t know if Crosman will sell them to the public, but you could ask.

    If not, the gun has to go to a repair station.

    I doubt the oil trick will help in this case.


  13. I have a Bengamin Sheridan HB17 air pistol which I use to scare off raccoons that are eating our garden. The pistol is only a year old, has been fired only about 50 times, is NEVER pumped more than 3 times (I don’t want to kill), and now it leaks through the barrel. I can hear it. One shot it was fine, the next it was leaking. I called Crosman, they said oil it. The manual only has instructions for oiling pivots. What can I do at home? Do I need to send it way for service?

    Any insight you could provide would be most appreciated.

  14. lagbolt1138,

    Have you stored your gun with a pump of air in it? If not, start doing that now.

    Your problem is your seals are hard and dried out from exposure to the air. Oil the pump head by turning the gun upside down and opening the pump handle as far as it will go. The pump head will barely be visible at the end of the pump slot. Drop four drops of Crosman Pellgunoil or any PURE silicone oil (edible oil only!) on the pump head And work the pump handle for 30 seconds to spread the oil.. Don’t use 3-in1, WD-40 or any household oil or the gun will have to be stripped and repaired.

    After oiling, pump the gun eight pumps and shoot it with a pellet. Do that 10 times. Then put two pumps of air into the gun and let it sit for a day. In 24 hours, cock the gun and shoot it. It should still be holding air. If so, your gun is fixed. Store it with a pump of air in it at all times.

    If that doesn’t fix it, you can try the same procedure again, or write me and I’ll tell you where to get it fixed. Stored with air in it, your pistol should last 30-40 years.


  15. BB-

    Wow. Good stuff there. I will try it tonight. Thanks!

    While I have you…another question.

    My wife has difficulty with the pumping of the HB17. She’s not nearly my size, so we’re considering a CO2 BB pistol for her on raccoon watch.

    How long will a CO2 cartridge (CO2c) hold pressure in a pistol after installed? Using up an entire CO2c for just a couple of shots is wasteful and expensive. Since budget is an issue, especially on such a low use item, can you recommend some mfgrs or models to look at or avoid? It would be best to have something ready for use, than to waste time on set up.


  16. An airsoft gun will scare a critter without damage, while a BB can possibly break the skin.

    You can buy a good automatic electric gun that runs on batteries for under $30.

    Look under Airsoft and then under electric mini machine guns on the Pyramyd AIR website.


  17. BB-

    A quick follow-up on your air leak fix for the HB17 (see 06 June posting). The oil procedure you recommended worked perfectly. Thank you so much for time and expertise.

  18. i have a crossmen power master model 760, i’ve had it for 10 years and it just started leaking out the barrel and im stumped, any help would be appreciated

  19. BB,

    I have a Crosman Model 73 CO2 rifle. I think it dates from 1976, and has probably never been oiled.

    After years of sitting on a shelf, I tried to get it working again. When I insert a CO2 powerlet, most of the time I get a fast leak that empties the cartridge in 5 – 20 sec. I have tried to use WD-40 and some oil to seal the leak (not Pellgunoil), to no avail. Do you think I made the problem worse? What do you think I should try next?

    Thanks for the great site.

  20. JCG,

    Well, the oil and WD-40 didn’t do it any good. WD-40, especially, is very rough on fine working parts. It’s great for drying distributor caps, but who has one of those anymore? I love the smell, but when I saw what damage the varnish it leaves can do to a fine firearm, I stopped using it altogether.

    I would say that the best thing you can do now is to send your rifle to a good Crosman repair station. Here is the best:

    Rick Willnecker Contact him at airgunshop@aol.com or call 717-382-1481.


  21. Hello! I have an old Crosman 760 purchased around 1976. It’s still a good gun, but recently it’s developed some kind of leak. The first shot is always fine, but after that, it won’t hold any pressure and it’s a really weak pffffft no matter how many times I pump it. Then I let it sit for a day or so and it’s fine for the first shot again, but after that, no go. Is there any way to tell which seals or valves need to be replaced, where can I find parts and how do I go about it. I’ve already disassembled the gun about as far as I can but I think there are still some parts in the barrel. Thanks!

  22. There are no parts in the barrel. The entire valve is housed in the pump tube under the barrel.

    You can call Crosman and see if they will sell you the parts you need, or you can send the gun to an airgunsmith. I recommend this guy:

    Rick Willnecker Contact him at airgunshop@aol.com or call 717-382-1481.


  23. i have a hahn 45 co2 bb gun its old i just recieve it from my grandpa i put a co2 cartridge in it when i go to shoot it leaks where the inlet is sprays out like and five seconds then its emtpy. what do i do

  24. I have a Crosman model 1077 repeater rifle. It’s been sitting for about ten years because it developed a fast leak so I just put it away. Now my neighbor is having that raccoon problem that it seems, everyone is having so we need to try harsher measures. He’s already trapped 8 of the critters. Thing is, our township and county want nothing to do with them. They said to call private animal control people who, by the way, get big $$$ for their work! Town told us that you CAN NOT trap them and drive them to a remote location as it’s a crime to transport wildlife ANY DISTANCE without a license. Private pro suggested .22 cals or 12 gauge. Right…..at 2 am with neighbors sleeping 20 – 30 feet away.

    Anyway…..want to get the gun working so as to put a little “scare” in them. Can’t kill them cause we can’t dispose of them without getting arrested so….where do I start with this leak thing? After I put the cart in you can hear it hissing.


  25. got my hands on crosman 38t 177 air gun. I don’t know much about it. I bought a box of 5 CO2 gas and pelts. Placed CO2 and took one shot at night, placed the gun on table only to hear hesssssssssing while watching tv. The CO2 gas gone. I took gun apart in the morning tried different things placing CO2 cartg till I used all. It is leaking gas and I can’t find out from where? some gas came thrugh the cylender some through barrel. Please help Thanks….

  26. B.B.

    Above you mentioned the Crosman maintenance kit.

    I noticed that PA discontinued it, so I'm wondering if putting a few drops of Pellgun Oil on the inlet, & a couple on the cart do the same thing?

    – The BBA –

  27. B.B.

    Yes I understand that, but I meant for FIXING leaks, not finding them.

    That's my fault, I should have been more specific.

    Pellgun Oil IS great stuff & HAS fixed a number of leaking guns of mine. But in my experience, usually just the slow or moderate leaks. Not the ones that completely empty a CO2 cart in a matter of seconds.

    I have a couple of REALLY bad leakers like that, & while of course I don't expect Pellgun Oil to work every time & especially not on guns where the seals are totally shot, I'm just trying to find out what will give me the best chance.

    The description of the cleaning kit says;

    "Includes two Pellgunoil Lubrication Cartridges and 100 felt cleaning pellets."

    Since Crosman doesn't say how much oil is in their Lubrication Cartridges, I'm just wondering if they are more efficient or will work better, as opposed to putting a several drops of Pellgun Oil on the inlet, & also a couple on the tip of a plain CO2 cart?

    I've actualy saved some pretty bad leakers by doing that a few times.
    It didn't work the first time, but the second time it seemed to slow down a little, & by the third or fourth time, it DID work. 🙂

    So I was just wondering if the Lubrication Cartridges would work better, & save some guns that my method won't.

    – The BBA –

  28. B.B.

    Yeah… That makes sense.

    The more I think about it, how much oil is really in those lube carts? Five or six drops?
    Even if it were more, my method would still eventually get the same amount of oil in the same places, within a couple of tries or so.

    I guess it was just wishful thinking, hoping maybe there was something I didn't know about them, but the more I think about it, it's like you say… Either way, it's going to do the same thing.

    Thanks for the input & bearing with my silly questions lately.

    It's been a rough month, so my brain is scrambled right now, & I'm finding myself second guessing everything.

    Thanks again,

    – The BBA –

  29. Alexander,

    Your gun has a leak that has to be repaired. A seal is bad. Have you always used Pellgunoil with every new cartridge? That can prevent this from happening, but sometimes the seals just fail.

    Contact Crosman for repairs unless the gun is under warranty.


  30. I got an old crosman 38c from my dad put a co2 cartridge in and it all leaked out. so I’m soaking the cylinder with the air parts in tranny fluid this should swell the seals. but if it don’t where is this guy in Pa? thanks

  31. I have a Daisy Powerline 990, you can hear air leaking out when you pump it more than 7 times, it seems to be coming from around the chamber. How can I fix it?

    • You can try some Pellgunoil on the pump piston head like it shows in the manual (which is online at Pyramyd Air) but a fast leak usually means the gun needs to be resealed. Daisy does sell the seals, if you are handy. Otherwise, call Pyramyd AIR.


  32. Well, Hoppes may have ruined the gun!

    It may need a complete rebuild now.

    That's why I specified Crosman Pellgunoil or 20-weight non-detergent motor oil. Nothing else works. Your owner's manual should have mentioned that.

    Because it is a Daisy, only Daisy will repair it.


  33. B.B.

    I have a Crosman 357 Co2 powered air pistol. I used WD-40 on the end of one air cartridge before knowing what sort of harm it would do to the airgun (that was a stupid idea).

    Now the airgun is no longer consistent with each shot I fire. i.e. I fire one shot and its perfectly normal, then I fire another shot and the velocity of the pellet goes down by half etc… But when I wait for about 60 seconds after each shot the velocity of the pellet returns to normal. I don't hear any leaks and I just got this gun about a month ago…

    Would Crosman pellgunoil fix this problem? Or would this problem fix itself over time? What would you recommend?

  34. I had this exact problem filming a shoot for American Airgunner today! The problem is not lubrication. It is the piercing needle that isn't puncturing the CO2 cartridge deeply enough. It leave a small hole the gas can eventually get through.

    Either the piercing pin has to be replaced or you need to screw the cartridge in tighter.


  35. Or you need to shim the bottom of the cartridge like I had to do on my crosman mark II since the piercing needle had been worn significantly. I put a doubled over thickness of paper towels at the bottom of the co2 cartridge, then put pellgunoil on the tip of the cartridge. After 3 cartridges the gun shot like it was new. I'm convinced that B.B.'s pellgunoil was as significant to this "fix" as adding the doubled paper towels to increase cartridge penetration.


  36. Good point! I'll give that a try. I think I might need to replace the piercing needle though because I don't hear that discrete hiss when I screw the cartridge in.


  37. Thanks Kevin! I will also give that a try without replacing the needle first. I thought the WD-40 contributed to the problem or messed up the seals badly… I'll have to give pellgunoil a try!


  38. Anonymous with the piercing needle problem,

    Please visit the link I provided. There's some interesting comments to your questions from experienced airgunners waiting for you there.


  39. Anonymous,

    I would like to add that when using Pellgunoil, sometimes you have to go through a number of carts before it starts to work.

    I had one gun that took 6 carts with putting pellgun oil on them before the leak finally stopped.

    So, if it doesn't fix it the first time, don't give up.

    Hope this helps,


  40. Anonymous regarding the piercing needle problem,

    My apologies. I confused you with another airgunner.

    I am going to give you a link though.

    You posted your question under an article that B.B. wrote back in 2005. Not many airgunners check back on these old articles. Most are asking and answering each others questions in the "comments" under the most recent article that B.B. has written (B.B. writes a new airgun related article every day, Monday-Friday). Here's the link (you will need to copy and paste) that will always take you to the most recent article that B.B. has written:


    Look forward to seeing you there!


  41. i have a 38t, hapve taken it apart to investigatet a full blown leak. I have two 0 rings that are bad. Looking for replacements. cannot find on the internet—-


  42. okay, can someone really help me please. Here the story. I bought a Umarex SA-177 air pistol and for about a week its very nice and very good. Everything works fine, no leak or nothing. Well I'm the type of person who likes to keep gun loaded with C02 in it. For some reason when i pull back the Co2 out and put a new one in, the C02 just leak out fast, which if I don't tighten up the seal and if I do tighten up the seal, it will continue to leak slowly. By looking at the puncture seal, noting seem to be wrong. I even tried pellgun oil but it still had the same problem. I thought it might be the tightener (the screw that push the Co2 up and tighten it), but it's not. I can't find a solution to fix it. Can anyone please help me here, or at least some advice. Thankx

  43. Well, there is probably not too much that can be done about your gun at this point. But you might try putting Crosman Pellgunoil on the pump head and allowing it to work into the gun. It might solve the problem. You should have been oiling the pump head this way every six months.

    Read this report:


    If that doesn't work, you'll have to get the gun resealed.


  44. Anonymous, basically you've got a leaking valve.

    I don't think those 760's are particularly difficult to repair, at least if you're reasonably good with your hands. And parts are pretty easy to get – at least for some variants. I did a couple of older ones earlier this year.

    If it's a recent vintage it might not be worth the trouble of fixing. But if it's an older one you might wanna take a shot at it yourself.

    Maybe someone here can help you out:


  45. I have a Walther P99 DAO CO2 blowback airsoft gun and it just recently started a fast leak. Its really pissing me off. Ive wasted like 8 cartridges and still cant seem to fix it. Ive tried putting hockey tape on the cartridge to get a tighter fit but it didn't work. Any ideas?

  46. Anonymous,

    unfortunately, you've posted your question on a blog that's 6 years old! Only a couple of us monitor these old blogs. Re-post your question on the current blog. Try:


    Now, have you been putting any oil on the tip of your cartridge before inserting into the chamber? If not, probably your seals are a bit dry so try that. Pellgun oil is recommended but you can get away with 20 or 30 wt. motor oil. That may slow the leak and even stop it. The hockey tape won't help at all.

    Good luck.

    Fred PRoNJ

  47. hello, im not inquring about an air rifle persay, but about an airsoft rifle. i have a L96 Bolt action sniper rifle and i bought it used, he had it for about a month, and claimed it was in "very mint condition" he listed that it came with silicone oil as well, so im assumed he had maintained it well. when i recived the gun, it was excessivly oiled with WD-40 and i was wondering if there is any way to replair it without a huge budget. it doesnt have enough power to accuratly hit a pop can 30 feet away.

  48. Hi there

    I have a Crosman 1008 which has performed fine for the four years I have had it. I have never had a leak problem until the other day when I finally followed the instructions and put a drop of Crosman 241 Pellgunoil on a fresh CO2 caplet. Now it leaks (fast leak).

    Any advice? Thanks in advance.


  49. Ian,

    First of all, the Pellgunoil didn't cause the leak. Second, a fast leak is a seal problem. An o-ring might have hopped out of its seat or you might have torn the face seal when installing the last powerlet.

    At any rate, your gun needs to be resealed.

    Then ALWAYS use Pellgunoil.


  50. Dear B.B

    I have just recently bought a Crosman 760, and It's shot very nice groups (for the price), and the power is great for backyard plinking when pumped 10 times……however, when I pump it, I hear a 'swish' sound for a fraction of a second when I have opened the pump lever all the way……is this a problem, or does the cromsman 760 make a bit of a sound when you pump it ??


  51. AJ,

    Think about what is happening when you pump. The piston, or pump head, is being withdrawn from the compression chamber, creating a vacuum inside the chamber. When the piston passes the air inlet, air rushes into the compression chamber. That is the air you compress on the next pump stroke.

    All multi-pumps have a swishing sound when the pump handle is opened all the way.


  52. I have a ultra-fast leak, one that drains the tank in about 10 seconds. It's pretty intimidating with a "smoking" gun near me. It leaks from well…everywhere.

    I was told by the manufactor to get an o-ring rapair kit, and that it maybe at Cabella's. However, Cabella's must have something against the South East U.S., I mean it looks like a hole in the map. I can't find anything like that online, except for an air rifle repair shop that would charge more than my gun (which is worth $70)

    I'm not attached to the gun (maybe a tiny bit) but I don't want to get a new one simply because I don't want to spend the $50-$100 on it. What do you reccomend I do?

    please e-mail me at jas11101@gmail.com ; this is my spam account btw, just in case.

    Thank You!

  53. huntingmachine,

    It would help if I knew what kind of gun you have. But it sounds like you are talking about a CO2 gun. Your leak sounds like a torn face seal, located where the cartridge gets pierced.

    Have you always used Crosman Pellgunoil on the tip of evey new cartridge when you installed it? That and not over-tightening the cap are two things that preserve the face seal.

    Tell me what gun you have so I can tell you what to do next.


  54. huntingmachine,

    I doubt you hurt the seal by dry-firing the gun. There is no relationship between the inlet valve and the firing mechanism that I am aware of.

    But the P23 does have a thin face seal. I bet that's what it is. It could have been damaged by not oiling every cartridge with Crosman Pellgunoil, or by over-tightening the CO2 cartridge screw when you pierced the cartridge. A lot of times we think that screw needs to be very tight to prevent leaks, when the opposite is the case.

    In any event, I think your gun needs to be resealed. If Gamo won't do it for you, perhaps Pyramyd AIR will.

    Of course the P23 is so inexpensive that there is a point beyond which it's cheaper to buy a new gun rather than to fix the old one.

    Just remember to always use Pellgunoil from now on.


  55. Hay I have a 15 year old power master 760 it's leaking after 5 pumps I suspected it was the o ring took it apart and replaced it and it's still leaking I really need some help with this

  56. Guys any one please I have air soft pistol pro77 when ever I put co2 it empty it in 2 or 3 seconds just from every where any vedios or some one to call????? Any tips

  57. When they empty fast like that the seals are gone. You need to have the gun resealed. Pyramyd AIR can do the work.

    Sometimes over-tightening the CO2 screw when the powerlet is pierced is what ruins the seal.

    Just use Pellgunoil on the tip of each new cartridge after the gun is sealed and stop tightening the screw the moment it hisses. It will seal instantly that way.

    Good luck


  58. I have a Crosman 22 cal. 38T pistol. It is all metal. I bought in the early 1970's. I tried touse it one day and the co2 poewllet just discharges right out. Also the new pellets seem to move forward and stop it from revolving. The manual says to use super pells. Don't know where to find them of pelgunoil. Any ideas?
    Thanks, Pat

  59. Pat,

    put a drop of motor oil (20 wt is recommended but 30 wt will work just fine) on the tip of the powerlet and install it. The seals are probably hardened from age and also very dry. If that doesn't work (and you may have to do it two or three times), the gun will have to be re-sealed. As for pellets, they aren't moving forward due to the CO2 cartridge being exhausted from a leak.

    One last thing, keep in mind this blog is 7 years old and very few of us monitor them. Feel free to ask your questions, off topic is always welcomed) on the current blog.

    Good Luck.

    Fred DPRoNJ

  60. Pat,

    You buy Pellgunoil on this website. Look here"


    The pellets you mention are obsolete, biut far better pellets are now available. But you have to buy them online — they aren't sold at Wal-Mart.


  61. This stopped my gun from leaking… 100%. Take a
    latex glove and cut a 1/2 sq in. and pull over the
    neck of the new CO2 . this will need to be stretched
    a little . It is almost self holding, but just wrap very
    small rubber band or the tail you cut of the glove around serveral times. Works like a charm.. Crowhunter…..

  62. I have a Ruger p95 and while gassing up I accidentally didnt screw it in all the way and it leaked all out. I quickly put it on the bathroom floor,shut off the light, turned the fan on and let it be. But the question is the gas WONT kill me if I go in there right as of now its been in for around 10 mins.

  63. Bryce,

    Well, I'm guessing that you did finally go into the bathroom and the gas didn't kill you.

    CO2 is not poisonous. It simply displaces air and we cannot breathe it and live. Since it is much heavier than air it goes to the floor and is dispersed within a few seconds.

    To be dangerous the way you described, you would have to be in a very small airtight room with the CO2. Such a room would eventually suffocate you naturally, since you exhale CO2 with every breath.


  64. Hello, i got a Crosman 31, and it leaks from the pipe not very much but it sure leaks, i fixed the leak from the patron, juste used som regular oil lol O.o, but i don't know about the leak in pipe? plz help me

  65. Filip,

    I'm not sure what you mean when you say the "pipe." Are you referring to the barrel?

    Oiling the gun may not fix all leaks, but you should try this. Put more oil (Crosman Pellgunoil or 20-weight motor oil) in where the CO2 cartridge is pierced, then pierce a fresh cartridge. Now, shoot the gun without BBs several times (20 or so) very fast. That will blow the oil through the valve and let it get on every surface. If oil is going to stop the internal leak, this is the way to do it.


  66. Hey, my friend gave me a 303 BB pistol and i use it shot fine then i took off the cover bymistake and i put it back toghther then i put a co2 bottle and while am closing it it keeps leaking a dint shoot no more after 8 seconds…. Idk wats wrong but it runs out of co2 quick and cant barley fire

  67. I don't know what a 303 BB pistol is. Is it an airsoft gun? If so I'm afraid we can't help you here.

    Is it a pistol that shoots steel BBs? If so, who made it, or what company's name is on the gun?

    What do you mean by "the cover?" Are you referring to a part of the pistol such as the slide, or do you mean the place where the CO2 cartridge is installed?

    I assume that you have already tried the remedy recommended in this posting?

    This blog is very old and no longer active. Our new blog is a much better place to discuss this. Find it here:


    You do not have to stay on topic, so you can ask your questions (and answer this comment) there anytime.


  68. This got deleted by mistake.

    I got my Crosman 38t from my grandfather, and the first time I put a CO2 cartridge all gas leaked realy fast (+/-5 seconds). This is my first airgun and I don't know what to do. I tried applying pellgunoil, left it for a night, and in the morning I tried putting CO2 cartridge again and it also failed.
    If anyone can help me somehow I would be really thankful.
    Please reply through email: piotrlewicki3@gmail.com

  69. I have a Benjamin air rifle C9A series20 cal and I found that the muzzle is leaking air. I’d like to see if there was a way I could fix this since I’ve had it a long time and like to give it to my son when he gets a bit older .

    • Rich M,

      Welcome to the blog.

      The muzzle is where you hear the air leaking, but the leak is deep inside the action — at the valve. Have you used Crosman Pellgunoil on the pump head, as you are supposed to? That will usually take care of such leaks.

      If that doesn’t work (and it does work in 75 percent of the cases) then put some Automatic Transmission Stop Leak on the pump head. That will soften the seals and usually fixes things. Look at this post:


      If neither thing works, you gun has to be resealed.


  70. Hi i have a winchester model 11 bb gun and whenever i try putting a brand new co2 cartridge in it just goes out really fast from the barrel and i dont know what to do.

    • John,

      Have you been putting a drop of Crosman Pellgunoil on the tip of each new cartridge? That is the problem, I think.

      Your gun probably needs to be resealed by a repair station noiw. Fast leaks can’t be fixed by anything but fresh seals.


      • If the gas is leaking “out the barrel”, it sounds like more than just simple seals — something on line with a valve that isn’t closing after firing. Granted, there are seals on the valve and/or bolt (whatever is used to cock the action and feed the next round) but a rapid escape past those, without a noticeable leak around the cartridge nose seal???

  71. I have a Black Ops 8″ Exterminator, and the leak I have is coming from the hammer area. It’s not only a audible leak, but a -visual- one as well, as in bits of frozen Co2 are escaping from there. How in the world do I fix -that-?

    • Kazareh,

      Welcome to the blog.

      Unfortunately, guns like the Black Ops are made by processes that make them very difficult for the owner to repair. Parts are therefore not stocked anywhere. Your dealer will have to swap the broken gun for a new one.

      I’m sorry, but some things can’t be fixed.


  72. I have an old Crosman 766 phase II that is not catching/holding air. The pump has pressure and about 3/4 of the way down it looses the air all at once. I have replaced the rubber seal and a couple of easy access O-rings. It did not help!

  73. I am thinking the firing valve is the brass “thingy” with some parts hidden inside it. I have never taken it apart. I have taken the whole gun apart a few times. I actually replaced some of the parts last night and put it all back together with no success. I have replaced the itty bitty o-ring that fits in the hole and the larger outside O-ring of the brass part. I am assuming that the interior parts are needing replaced or something??

    • Joey,

      Yes, the firing valve is the brass assembly. The actual valve face looks like the illustration I drew for the outside lock gun yesterday:


      You need to replace the valve face which is synthetic. That’s what causes that kind of leak. It may just have a piece of dirt ground into the face and if that were cleaned off and the face recut, it would seal.


  74. Thank you and this has been so HELPFUL!!
    A couple more quick questions:
    Is the valve face inside the firing valve?
    There is a bit of roughness on the outside where it looks like the firing valve unscrews (where the large outside O-ring sits? You can feel them? Would that cause a problem?
    Also, do you know if the firing valve parts for the 2100 will work for the 766? I tried to order they entire valve assembly from Crosman for the 766 and it was no longer available. I did not ask at that time about the 2100 part??? I was thinking of getting just an entire new assembly to replace. The parts guy did not suggest another part, but it appeared he did not know much about all the parts from a couple of other “simple” questions I asked him.

    • David,

      Okay, I didn’t realize that you didn’t know. When you pierce a CO2 powerlet you should ALWAYS put a drop of Crosman Pellgunoil on the tip of the cartridge. The oil then gets blown through the powerplant and gets on all the seals and o-rings inside. It happens automatically. All you do is put it on the tip of the new cartridge before you pierce it.

      I guess you haven’t been doing that? That could be why you have a leak. Maybe you don’t have to use the Transmission Stop Leak right now. Maybe all you need to do is oil the next cartridge.

      DO NOT USE HOUSEHOLD OIL! 3-in-1 is great stuff, but not for this. If you don’t have any Pellgiunoil you can also use 20-weight non-detergent motor oil. It’s a waste to buy a quart for this, but it is the easiest way to oil the gun.

      You won’t find Pellgunoil at the discount stores. Buy it from online dealers like Pyramyd AIR. Look here:


      Read the reviews. 271 people gave it 5 stars, so it must work.

      Now it is also possible that you have a nicked or a broken seal or o-ring. If that is the case, no oil will help. The gun will have to be repaired. The Pyramyd AIR tech department can help you there.


    • David,

      Yes, that is your exhaust seal. Either there is a deep nick on its face from dirt or else there is a large piece of dirt embedded in the seal right now. The seal isn’t closing and the white that you see is CO2 gas condensing in the atmosphere. It sort of looks like snow spraying out.

      Your gun probably needs to be resealed.

      After that always use Crosman Pellgunoil on the tip of every new cartridge.


    • David,

      You didn’t get on my nerves. This blog is run for people in your situation. We are here to help.

      I found your questions were well-formed and easy to understand. You just didn’t understand what I was telling you and were smart enough to ask for a better explanation.

      Stay with us and ask anything you want.


    • The shop would probably prefer using a parts kit they are familiar with.and if they get the wrong one they’ll make it right, if you get the wrong kit you just wasted your money.
      I used to work in an automotive repair shop and when people brought their own parts the job was avoided like a plague and they were charged full shop labor rate($75/hr),furthermore
      while our parts came with a lifetime warranty we couldn’t warranty someone else’s parts so all they got was 90 days warranty on the labor.
      Just not a good idea or way to start a relationship.

  75. Hey B.B if your still active on this, i have a Umarex NXG APG pneumatic multi pump air rifle, and every time i pump it, it seems to leak out, and im not sure what to do, it its unfixable or magic pellgun oil can fix the valve, but i dont hace access to pellgun oil, is there any other house hold substance i could possibly usr in substitution of pellgun oil? Cooking oil, or wd40 perhaps?

    • BrandonM177,

      No to cooking oil and definitely never use WD-40, which is a solvent.

      If your country does not have Pellgunoil, try non-detergent motor oil. Thirty weight works the best, but Pellgunoil is 20-weight.


      • Appreciate the feedback, but i took the gun apart and found the problem, its the valve, is there anyway i can fix it without replaceing it? Its a fast leak on 1-4 pumps, and a slow leak at 5-10 pumps. TIA

    • I do not have an 880 but I have read that you must first cock the bolt and leave it in that position, if you do not it will have the leaking problem that you describe. If you are cocking it first and it still is leaking then you may have a valve problem.

  76. I have a very old crosman air 17 pellet rifle single pump and it leaking out of the barrel very bad it peunamic also and i figured i just needed to oil it but its like 18 years old and i followed the instruction to put 3 drops of oil in it but seeing its so old and it hasnt been used in years should i put alot of it ?if so how much so i dont over oil it ?

    • Jmonezzy,

      Welcome to the blog.

      Your AIR 17 is a single stroke pneumatic. The pump seal is also the inlet seal and has gotten hard over the years. Regular oil will probably not fix it.

      It might work to use 10 drops (yes — 10) of Automatic Transmission Stop Leak. That will soften the pump piston and the other seals. Nothing else will probably work at this point.


  77. hi i have a daisy poweline 990 dual and the pump action on it works but whenever i put in a co2 tank it all spills out and i can only manage to shoot one shot before its empty any advice or help you can give is appreciated.

    • luis,

      Welcome to the blog.

      Did you put a drop of Crosman Pellgunoil on the tip of the CO2 cartridge before piercing it?

      I can’t tell from your description how long the gas takes to escape — 1 minute or three. You can put several drops of ATF sealant on the next couple cartridges before piercing and they may fix the problem. You may have to go through 2 or 3 cartridges before the gun seals. If there is a piece of dirt on a seal, or if a seal needs to be blown into its channel, this often works.

      Otherwise, your gun has a broken seal and needs to be repaired.


Leave a Comment

Buy With Confidence

  • Free Shipping

    Get FREE shipping on qualifying orders! Any order $150+ with a shipping address in the contiguous US will receive the option for free ground shipping on items sold & shipped by Pyramyd AIR during checkout. Certain restrictions apply.

    Free shipping may not be combined with a coupon unless stated otherwise.

    View Shipping Info

  • Shipping Time Frame

    We work hard to get all orders placed by 12 pm EST out the door within 24 hours on weekdays because we know how excited you are to receive your order. Weekends and holiday shipping times will vary.

    During busy holidays, we step our efforts to ship all orders as fast as possible, but you may experience an additional 1-2 day delay before your order ships. This may also happen if you change your order during processing.

    View Shipping Times

  • Shipping Restrictions

    It's important to know that due to state and local laws, there are certain restrictions for various products. It's up to you to research and comply with the laws in your state, county, and city. If you live in a state or city where air guns are treated as firearms you may be able to take advantage of our FFL special program.

    U.S. federal law requires that all airsoft guns are sold with a 1/4-inch blaze orange muzzle or an orange flash hider to avoid the guns being mistaken for firearms.

    View Shipping Restrictions

  • Expert Service and Repair

    We have a team of expert technicians and a complete repair shop that are able to service a large variety of brands/models of airguns. Additionally, we are a factory-authorized repair/warranty station for popular brands such as Air Arms, Air Venturi, Crosman, Diana, Seneca, and Weihrauch airguns.

    Our experts also offer exclusive 10-for-$10 Test and 20-for-$20 Service, which evaluates your air gun prior to leaving our warehouse. You'll be able to add these services as you place your order.

    View Service Info

  • Warranty Info

    Shop and purchase with confidence knowing that all of our air guns (except airsoft) are protected by a minimum 1-year manufacturer's warranty from the date of purchase unless otherwise noted on the product page.

    A warranty is provided by each manufacturer to ensure that your product is free of defect in both materials and workmanship.

    View Warranty Details

  • Exchanges / Refunds

    Didn't get what you wanted or have a problem? We understand that sometimes things aren't right and our team is serious about resolving these issues quickly. We can often help you fix small to medium issues over the phone or email.

    If you need to return an item please read our return policy.

    Learn About Returns

Get FREE shipping on qualifying orders! Any order $150+ with a shipping address in the contiguous US will receive the option for free ground shipping on items sold & shipped by Pyramyd AIR during checkout. Certain restrictions apply.

Free shipping may not be combined with a coupon unless stated otherwise.

View Shipping Info

Text JOIN to 91256 and get $10 OFF Your Next $50+ Order!

* By providing your number above, you agree to receive recurring autodialed marketing text msgs (e.g. cart reminders) to the mobile number used at opt-in from Pyramyd AIR on 91256. Reply with birthday MM/DD/YYYY to verify legal age of 18+ in order to receive texts. Consent is not a condition of purchase. Msg frequency may vary. Msg & data rates may apply. Reply HELP for help and STOP to cancel. See Terms and Conditions & Privacy Policy.