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Can CO2 guns be left charged?

by Tom Gaylord, a.k.a. B.B. Pelletier

Today is the Memorial Day holiday in the U.S. It’s the day we honor those who have given the ultimate sacrifice to defend our nation. Edith and I would like to join the rest of the country in remembering all these heroes from the Revolutionary War down to today.

This report covers:

• Technology advances as time passes.
• Not all guns changed over time.
• What about 88-gram cartridges?
• How does a charged gun suffer?
• How long can a CO2 gun be left charged?
• Can you leave a CO2 gun charged?

I’m writing this report for my good friends at Pyramyd AIR. They get questions all the time about this topic, and they wanted me to discuss the whole story. It’s long, so sit back and enjoy it.

Gas gun technology advances as time passes
In this case, the technology refers to both the design and the materials. In the 1940s, Crosman made CO2 guns that were either charged from a separate bulk gas tank or else the bulk tank was attached directly to the airgun. The gas flow in these guns was very direct — from the tank through the valve and out the barrel.

Crosman 116 pistol and bulk tank
The Crosman 116 bulk-fill gas pistol was based on 1940s technology. Gas flow was simple and direct.

The seals in these guns were an early form of synthetic material that hardened and failed over time. But in recent years, all the vintage seals for these guns have been reproduced in modern synthetics that have a much longer shelf life and even longer operational lives. When a vintage CO2 gun is fixed today, you can expect it to last a very long time. A gun that might have leaked after 20 years of service in the 1950/60s can be resealed today and not leak again for the next 40 years because of the advances in materials.

In the 1960s and after, the design technology changed. The gas flow in these guns was not always as direct as it had been in the earlier guns. Airgun manufacturers were now making lookalike guns, and they were being constrained to put the CO2 cartridge in certain places such as the grip, where the gas might have to flow for some distance to get to the breech. Small metal pipes were used in some gas guns to transport the gas from where the cartridge was pierced to where the gas was needed. These pipes could not stand up to the pressure of a constant charge, and it was best to leave them discharged until you wanted to shoot the gun. This marked the start of gas guns that could not be left charged.

Another change was the invention of the magazine that also contained the gun’s firing valve. All the seals were in that tiny unit on top of what looked like a conventional pistol magazine. In these guns, the small flat end of the CO2 cartridge was pressed tight against what’s known as a face seal by some kind of tensioning mechanism in the bottom of the grip. When the cartridge was pressed flat, the end seal stopped gas from flowing out around the end of the cartridge; and it only flowed straight into the small firing chamber. The valve held this chamber closed until the action of the hammer opened it with force, allowing some of the CO2 gas to escape.

Makarov Ultra magazine
The entire valve of the Makarov Ultra is contained inside the magazine’s silver top.

Face seals usually work quite well, but there are some things about them that you have to know. One is their thinness. If they’re twisted while the CO2 cartridge is pressed against them, they can tear. If that happens, they’ll leak. This is a good reason to always use a drop of Crosman Pellgunoil on the tip of each new cartridge before it’s pierced.

Another thing you have to know is the length of the CO2 cartridge. If the cartridge is too short, the flat spot may not press tight enough against the face seal even when the tensioner is adjusted as far as it will go. That lets the gas leak out because the face seal cannot do its job. The solution for this is to try a different brand of CO2 cartridge.

Not all guns changed
As the technology changed, all gas guns did not change to use the latest designs and materials. The cheaper guns did go the way of face seals, gas tubes and lookalike designs; but there were more expensive gas guns costing hundreds of dollars that continued to rely on the older designs from the early years. These employed the very latest in materials in these designs. I’m referring to the gas guns used for formal target shooting. These airguns will hold gas for years without a problem because they are designed to.

What about 88-gram CO2 cartridges?
This question always comes up. While a gun that uses a 12-gram cartridge may shoot 50 or 60 times per cartridge, guns that use the much larger 88-gram cartridges can shoot hundreds of shots before running out of gas.

Walther 88-gram CO2 cartridge
The 88-gram CO2 cartridge is much larger than the conventional 12-gram cartridge. It contains much more CO2 gas, and, as a result, some thought has to be given to when it is used.

Should you remove an 88-gram cartridge after your shooting is done? In recent times, Crosman made a special adapter for their 1077 repeater (among other guns) to accept an 88-gram cartridge. That adapter has a valve that allows you to turn off the gas. The cartridge can remain on the gun, but there’s no gas flowing to the valve. I’ve had my 1077 with this adapter charged this way for several years.

Crosman 1077 CO2 rifle
Crosman’s 1077 repeating pellet rifle was made for a single 12-gram CO2 cartridge. Crosman used to sell an adapter that allowed the use of 88-gram cartridges.

Crosman 1077 gas system detail
The Crosman AirSource adapter shown here allowed the use of 88-gram cartridges. The knurled knob at the bottom of the vertical tube allows the gas to be turned on and off. This gun still has gas after being stored for 3 years!

Not all airguns that use 88-gram cartridges have a valve to turn the gas off. Shooters who use the 88-gram cartridges costing several dollars apiece must consider the shooting they are about to do to determine the probable number of shots that will be fired because some guns may suffer if left pressurized. If you plan on removing a 300-shot cartridge, better to do it after 275 shots have been fired, rather than only 25 shots. That would be like opening a $200 bottle of champaign so a friend could have a sip.

How does a charged airgun suffer?
A couple years ago, I asked Ed Schultz, Crosman’s top engineer, what damage is done when a CO2 gun is left charged. He told me that some of the modern seal materials can take a set if left pressurized too long. This was the first time I’d ever heard that; but since Ed is in charge of making the guns, I have to accept that it’s true.

There’s a second reason why the gun manufacturers don’t want their guns left charged, but they will never mention it: Liability. You see, a CO2 gun can shoot anything that’s in its barrel. It doesn’t have to be BBs or pellets. So children and irresponsible people can load things into a gun and shoot them even if they don’t have a supply of the correct ammunition. For this reason, a charged CO2 gun is a loaded gun.

How long can CO2 guns be left charged?
This is where the question gets personal. There are owners who obey the letter of the instructions and see it necessary to remove the cartridge within 5 minutes of shooting. If they planned on shooting again tomorrow, they would still remove the cartridge today.

Then, there are the more broad-minded owners who believe that they should remove the cartridges only when they think they’ve finished shooting the gun for a longer time. These are the people who will leave a cartridge installed for a week of shooting. I tend to agree with this group. But, sometimes, they forget what they’re doing and the cartridge never comes out.

The manuals are vague on this point, and I wouldn’t expect a firm answer from an airgun company, either. They have to defend themselves in court for whatever irresponsible actions are taken by those who use their products, so they can’t afford to give them any basis for a lawsuit.

I’ve left my modern CO2 guns charged for years, and eventually they all seem to leak down. Some will hold for more than a year, but eventually they all do seem to leak down.

My vintage CO2 guns, on the other hand, are always charged and never leak. They are like PCP guns, in that respect.

Can you leave a CO2 gun charged?
All of this brings us back to the original question — can CO2 guns be left charged? The answer is sometimes “yes” and other times “no.” It depends on the design of the gun in question.

These days, I tell people to follow the instructions in the manual but not to be anal about it. They can leave a gun charged overnight and even for several days; but before it’s put away, if the instructions tell you to remove the cartridge, that’s what you should do.

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.

78 thoughts on “Can CO2 guns be left charged?”

  1. On the topic, I’ve had the cartridge in the new XBG pistol for about 5 days, shooting a clip a day, which means it has another three days to go approximately because its getting a little more then 8 clips per powerlet! Thing is great on gas, about 160 shots, and that’s with the spring shimmed to give it a little more punch, it got a bit louder, though its probably just wasting gas now without a longer barrel to utilize the increase in expulsent… er, propellent…

  2. B.B.,
    You raised my brow when you mentioned the fact that any charged CO2 gun is a loaded gun.In comes the Dirt Daubber;These wasps attack & stun or kill spiders as a food source for their young.They spin these into a coccoon and bury in mud along with it’s egg sac.They will do this Anywhere they can fit their narrow bodies.While the Daisy buck I picked up had one of these stuck in it,it didn’t have enough power to blast the wad out(and required disassembly) a Co2 gun may have& a bucha flyin’ spiders and baby wasps is enough to get any body in trouble for a long time!
    May be a bit morbid but think about it.


  3. I never was much on CO2.Cartridges have to be purchased & replaced opening the question of attainability.I’ve been keeping an eye out for 88 gram cartridges available locally for price comparison purposes. It’s been a year now! Even 12 gram cartridges have not been in stock for some time now. This coupled with the” inexpensive” look- alikes of the ’80’s&’90’s having weak velocity & low shot count burned me out on them. My last one was a Crosman 1008 which I thought had totally ended my relationship with this power plant. Thanks to an education I now have an idea of how to make this system work for me and am considering giving it another try. 2240 , Please be kind?!


      • Yes,I remember well!It was a very well timed blog to me considering the fact that I had just begun my search for a gun that required less than 2 hands to operate effectively. I just need to come up with a hundred bucks or so that I don’t need to spend on other stuff like …? Who am I kiddin’? Gotta phone call the other day from one o the hospital services,They itemized the bill over the phone and then requested either a debit or credit card number,-$11388.98! I politely declined and informed them of my application for assistance in these matters.


        • Im sorry ti hear about your medical bills Reb, I hope you can find some relief with that. I definitely understand having to choose between the big bills and things we love and desire. You seem like a chin up kinda guy so I know things will work out, can’t keep us airgunners down, we’re to numb to frustration!

          • I’ll just tell ’em~If Ya want Blood you got it~! It’s costing me $25 a month I don’t have, just to stay outta jail right now! One CPF(commitment to pay fine) away!
            And they wonder what happened?!


  4. I have had two of my favorite CO2 guns that got where they won’t hold air any longer. I soaked the seals of both in Pelgun oil. My Mackarov non-blow back bb pistol now holds air again, but the Tanfoglio Witness (brown grips) will not hold air any longer. When I replace the CO2 cartridge into the removeable magazine, the air immediately leaks out. I have a second magazine that works fine, so that is better than having a pistol that I can not use.

    A question please. The bolt on my Marauder works pretty “un-smooth”. I first tried a little silicone oil on it and it got better for a short time and now is back like it was before oiling. I read the manual and it says to use moly graphite EP grease, which I have ordered but not received yet. Is there anything else I can do to the bolt to smooth it up?

    2nd question. My Maruader is sighted in at 5 yards. at 10 yards it shoots about 3″ high. I plan to take it to an outdoor range and shoot it at 50 yards. They don’t have a 25 yard position with a bench. Where can I expect it to be shooting at 50 yards? I have not received my Chrony yet, so have the velocity adjusting screw one full turn out from all the way in. Mine was set 1 1/3rd out from bottom when new.

    • Jerry,

      Wait for the grease you ordered.

      As for the Bronco, 5 yards is pretty much the worst distance to sight in. The separation of the sights and bore mean the sights have to be jacked way up at close range to get the pellet up to the sight line. You will probably be on target or a little low at 50 yards, because of the pellets trajectory.

      The best sight-in distance is 20 yards. But if you don’t normally have that, you do what you have to.


      • Thanks for the quick answer.

        I have the Marauder sighted in for 5 yards because that is the length of my indoor range. I can shut the door and not bother anyone. I have the Bug Buster scope mounted on it and I shoot off-hand at 5 yd. b.b. gun targets. When I receive my Chrony, I plan to try to find “the sweet spot” of the Marauder and start shooting at the 50 yard range at our local rifle range. I also will ask if I can supply my own portable target frame and shoot on the 50 yard line range, but at 25 yards.

        I can’t shoot outside because we are in a canyon and sounds travels so well, we have to whisper outside to keep our neighbors from hearing everything we say. Only wrought iron fences are allowed, so no hiding behind a 6′ board fence. Right now, the outdoor range is my best solution for shooting the Marauder and enjoying it’s accuracy potential.

        • Sounds to me like you need to tell the neighbors to take a flying leap! Though it sounds like you have a homeowners association, but either way, airguns are legal, if your not shooting across property lines and its at decent hours, why worry so much? Stupid question I guess, if you read “the invisible airgunners” article then we all know the strange looks and questions meant to embarrass that we all avoid, but its a shame and we should fight it, take the stand!

          • listen to twotalon. you (obviously) ain’t no lawyer and mostly tangling pa-tootie with one’s home-owners association results in a big no-win situation for everyone, especially for you. Unless you got unlimited funds to dabble in legally ridiculous Civil Law with the expectation of making a Supreme Court appearance, best to not dispense legal advice.

            • Oh ho, you got me! Im looking at it from what I would do if I had private property, I rent. I haven’t had the ability to enjoy my own yard and home and have my own place to shoot so I could NOT use it over unjustified fear of persecution….. No, Id move before letting nosey neighbors stop me from doing what I love, and legally can, do. Do you know of a place you want shoot an airgun on tour own private property? Your comment makes it quite obvious that your not happy with me having called you narrow minded, but if my neighbors were narrow minded, Id call that out too so don’t feel too bad.

              • Sorry, can’t, not want, and I believe you meant are not a lawyer, and no, as we’ve established, no one here is a lawyer, but to me it sounds like playing horseshoes in his backyard would be no different, and the question arises out of pure appearances. Why is this a legal discussion? Aren’t airguns popular because of their legality, and backyard friendliness?

                • I appreciate your stance on the subject of being able to shoot where you want to. In our old neighborhood, we had a 6 foot board fence separating us from our neighbors. We had a good backstop and no one complained when we shot our airguns. In fact, most of the neighbor kids shot with my kids and had their own airguns.

                  We moved to this part of Texas to be next to our son and his family, when we retired. It is a beautiful part of Texas pretty much unique to this area. I have been “a gun guy” for most of my life. I have a concealed handgun permit and a pretty large collection of fire arms and airguns. My neighbors all know I have, and shoot guns. Many have been to my home to shoot in my small range upstairs. At least 5 have bought air pistols because of their experience shooting inside my house. 2 more have purchased hand guns. Would we like to shoot outside? Of course. But, it would then put us in a controversial position and would start alienating those who share our neighborhood.

                  Just my 2 cents

                • In Michigan, pellet pistols (those with rifled barrels) are registered just like handguns. While the FED doesn’t control air gun sales, states and cities can and often do.

                  While the ballistics of pellets limits their effective range, they are still capable of shooting past most residential yards (I doubt you have a 100×100 yard residence) — any projectile that has the chance to leave the property line will likely be highly controlled. Even blooming archery equipment. Horseshoes and croquet balls are unlikely to travel far enough to be a problem (though the typical croquet layout tends to require use of two adjoining front yards). Practicing shot put could be a problem too.

                  Now, if your lot is completely fenced in, you have a shed on the back lot line in which you install a pellet trap and target, leave the door open, and then open a bedroom window, you might get away with shooting from the bedroom into the shed.

              • Here’s where you’re going wrong. Your status as a “renter” as opposed to a “owner” is absolutely irrelevant. Acquiring the use of the property, as either “owner” or “renter” where a home owners association is extant absolutely required you to sign a legal document agreeing to the terms of the home owners association. (Or something like it.) Normally, the intent of such an agreement is to keep you from erecting a view-blocking second story or ham-radio antenna, or piling your rent-a-wrecks in the front yard, or worse. I won’t go into what “worse” may mean, other than to observe that the creativity of a certain type of human to engage in abhorrent behavior is legendary.
                That “home owners” agreement certainly carries the force of law; In other words, if it says “No shooting in the back-yard,” you are automatically wrong to think you are legally “right.”
                I’ll say that again, just to make sure everyone gets it. Be very sure of your legal ground before you make a stand based on where you’re standing.
                As a renter, you need to pay particular attention to this agreement as flaunting it, in most jurisdictions, will guarantee (very) prompt eviction with little, if any, recourse to the (now former) renter. (AKA, meet your local Sheriff.)
                And understand, it’s not a 2nd Amendment issue, it’s a “failure to abide by the terms of an agreed upon contract, ” issue.
                Welcome to “Civil Law.”

        • Once you get the chronograph — plug the pellet, velocity, and bore-scope height into Chairgun… Set your target zero, and set the scale sufficient to show PoI at distances that match your indoor.

          I need to remeasure all my rifles as the new computer lost the databases from version 3 and version 4 is all sample guns…

          Taking my .177 Marauder, ~872fps with 10.7 (as I measured years ago) H&N Baracuda Match (not in current Chairgun database, used regular Baracuda but kicked the mass up to 10.7gr), and a scope height of 2.5 inches (large objective bell, high mounts) with a 50yard zero (and 1″ diameter “kill zone”) I get
          a 5 yard PoI of -1.62 inches, and a first (ascending) zero near 18 yards — and a gap from 23 to 45 yards where the pellet is above the “kill zone”.

          With the zero set to 44 yards, the pellet is within that 1″ diameter “kill zone” from 14.3 out to 49.2 yards, and the first zero is at 20 yards.

          • I was not familiar with “Chairgun”, but Googled it and found a source for it. Thanks!

            Do you mind giving me an e-mail address where I can contact you when I get the Chrony and start my testing? I am sure I am going to need some assistance.

            • I’m pretty sure at least a third of the regulars here could help with Chairgun questions. The tricky part I’m finding is getting it to save modifications from the default set of tabs. And I haven’t used the recent version that much.

              The basic factors are to select your pellet (click the pellet shown in the tab), confirm weight of pellet, set velocity from the chrono, set scope height, set desired zero range, and maybe “kill zone”.

              Then it becomes a game of just trying variations… Change the zero distance, tweak the velocity… If really insane, start adding cross winds (one of the displays will show the view from a scope with various reticles and powers so you can see what a cross wind will do to you).

      • I have a new problem. I had just put a new loaded magazine into my .177 Marauder and had greased the bolt, trying to smooth it up. I worked the bolt several times and then tried to close it on a pellet. The bolt would not close but ran into something about half way in. I tried re-cocking it and then removing the magazine. It was stuck tight. The magazine has about 1/16 inch of movement only and refuses to come out. I am assuming that I got a pellet half way out of the magazine and half way into the chamber.

        I got a dowel stick and tried to push the pellet back and it will not budge. So it is cocked and the full magazine is stuck.

        I will be most appreciative of your suggestions of how to get out of this jam.


        • Jerry,

          Every time you worked that bolt you fed another pellet into the rifle. When the bolt refused to enter, the magazine was empty and the pellets were lined up inside the barrel.

          Use a steel cleaning rod to tap the pellet backwards into the mag. You will have to work the mag from side to side to break off the lead pellets. After the mag comes out, you can pus the rest of the pellet out of the barrel.


            • Hi Tom,
              I found an old (never used) Beeman air gun cleaning kit from the early 80’s and now have a metal rod (brass). I pushed on the muzzle end and made about a pellet’s length of distance. I assume one of the pellets is back in the cartridge. The cartridge is stuck fast with just a little bit of movement when I tried to push it off of the breech. I know I am going to have to break off a pellet or crack the cartridge case. My guess it would be less damaging to use something to drive the plastic cartridge off the exact way it is put on. I was thinking about using the plastic blunt end of a screw driver handle and slowly tap it to try to work it off.

              I am certainly open to ideas and in fact need some direction.

              I have felt stupid before, but I am going for a record here.

              By the way, the pellets are dome shaped RWS Exacts and the little peep window on the cartridge shows the number 7 (it is a .177) and I believe it was fully loaded when I attached it. The room left from the end of the brass rod to the start of the breech is about 4 pellet lengths. So I assume there are maybe 5 pellets left in the barrel.

              • Jerry,

                What you are calling the cartridge is the magazine — no? I just want to be sure I know what we are talking about.

                You will have to work the magazine in and out to break off the lead pellets that are stuck there. A screwdriver is a good way to do it. Remember, the magazine wants top come out the right side of the receiver.

                This takes time and patience, but this is how it is done. It may7 take you several hours of patiently going back and forth to fatigue all the lead that is stuck in the breech.


                  • Good morning B.B.
                    Didn’t sleep well last night listening to the rain we sorely need and thinking about the pellets in the barrel. I got up early, made coffee and went to work on the problem.

                    I used the butt end of a small screwdriver and a plastic hammer to tap with. I was very gentle with the tapping and worked the magazine back and forth until it finally fell away. I was able to shear the stuck pellet in two. Then I used the cleaning rod and was able to push out the remaining pellets out of the barrel. What a relief, that was! A couple more pellet parts fell out of the hole where the bolt slides. Then I removed the pellet pieces from the magazine and the remaining unhurt pellets. All in all I retrieved 4 good pellets and 8 pellet pieces.

                    I was wondering if you think I should run a wire brush in the barrel to make sure there are no more pieces stuck in the rifling?

                    Well, this horror story had a good ending, thanks to your help. I learned a very good lesson about working the bolt action with a loaded magazine in place. I love my Marauder and I was sickened by the thought that I had done something to it that was possibly destructive.

                    Once again, thank you for your help.

  5. B.B.,

    With warmer Spring temperatures, I started shooting a TAU 7. Through your older reports, I learned to put a drop of Pellgun oil on the head of each new CO2 cartridge. There is nothing in the manual about storing the pistol with CO2. What do you think?

    Thank you for a well-timed report.


  6. CO2 was my absolute least favorite energy source for air guns based on leaky 1970’s pistols and the added cost of the cartridges. Fast forward some 40 years and one of my beloved rifles runs off of carbon dioxide.
    However, you cannot run out and buy this bad boy at Walmart and I really wish you could. Based on the QB79 with a target stock it runs on 9 ounce paint ball tanks and can produce over 20 ft lbs in 22 caliber which is a real sweet spot in the energy department.
    Starting life as a basic 79 it went to Rich in Mich for a riser so it would fit all 9 ounce paint ball tanks and his power tune along with some trigger work. Stock it was about 8 ft lbs if I recall correctly. I added the heavier furniture when it came back to balance the weight.
    Fill up a common 9oz paint ball tank for $2.00 and this bad boy is good for pretty much a whole 500 tin of pellets. No hand pump, no 40 lb cocking effort, just shoot and enjoy. But I’d guess most seller prefer you buy the disposable cartridges.

    • Volvo,
      Awesome,I have considered getting one of them “Tuner Guns” in it’s original form and building it into a sweet PCP as a long term educational practice/have a nice gun for dirt cheap when I get done, type of project. glad yours is doing well! What ha you done to it so far?


    • Volvo

      It is always good to see you around. I seem to remember some young whippersnapper blogging this very rifle. It would be nice to see a part 2, with all the updates and improvements.

      I hope your summer buzzcut was uneventful this year, with no nicks to the ears or back of the neck.

      Your #1 fan,
      Slinging Lead

      • Slinging,

        I always enjoy seeing your avatar, even if don’t know whether or not that kitten made it out alive.
        Someday I may open for business again, just to finish what I started. Don’t tell anyone, but I really hoped Tom would comment just once. Even if it was a scathing remark about my abilities or heritage, I would have printed and framed it. Ah, but validation does not come that easy.
        I do seem overdue for haircut now that you mention it.
        Be well.

  7. B.B.,

    Thanks for today’s blog about CO2. This topic has been on my mind a lot lately. Over the last few months, I purchased both the .22 caliber Hammerli 850 Air Magnum and .177 caliber Walther Lever Action rifles both of which use the 88 g/90 g CO2 as you and many others know. All of my shooting is typically done on a Saturday or Sunday whenever I can fit in a 2 to 3 hours for indoor target shooting. The 12 g CO2 used in my pistols, the Crosman 1077, and the Daisy Winchester MP4 are just the right size for 2 to 3 hours of shooting. When I’m done, I take them out and store the pistol or rifle until the next time. The greater capacity of the 88 g/90 g CO2 was one reason I was hesitant to buy the 850 and Lever Action rifles. I thought it would take a much longer time commitment to fully consume that much CO2. Due to this holiday weekend, I was able to arrange more time for shooting last Saturday. I loaded my Walther Lever Action rifle with a Walther 88 g CO2. Fortunately I had already accumulated 23 of the Umarex rotary magazines with my various purchases. I got 522 shots out of that CO2, and it took me only about 3 to 3 1/2 hours to shoot them. Understand this, I was shooting rapidly to determine shot count and time without any great concern for accuracy. Today I’m going to load an Air Venturi 90 g CO2 and shoot 20 different pellets bench rested and standing off-hand more carefully for accuracy determination.

    I have often wondered if there is a cost effective way for the manufacturers of 88 g/90 g CO2 cylinders to manufacture them with a permanently installed check valve so that a partially used cylinder can be taken out of the rifle without losing the rest of the CO2. I’ve got a third party check valve that screws on to the top of the cylinder, but have not yet invested in a bulk CO2 tank for refilling the 88 g cylinder. As another blog participant pointed out, Michael I think, the up-front cost for bulk CO2 can be expensive, and unless I really use a lot of CO2, that cost may not be money well spent.

    The availability of the 2x12g CO2 adapter for the Hammerli 850 rifle is a very good accessory to have. It gives me an alternative to the 88 g CO2. Airgun Hobbyist publisher Tim Smith reported that Umarex has a 2X12g in-line CO2 adapter for the Walther Lever Action rifle, but said that Umarex distributes it only in Europe. Do you know anything about this 2X12g in-line adapter for the Walther Lever Action rifle?

    • Charles,

      I’m glad you found this report interesting. Yes, you do need tpo plan when you use those 88-gram cartridges! An inline valve would be wonderful, as Crosman has already demonstrated. Aftermarket guns that use large paintball tanks sometimes have them. Yes, it could be done, but no, I don’t know of anyone doing it.

      As far as the Umarex adapter to switch back to 2X12-gram cartridges — what a great thing! I will ask Pyramyd AIR to see if they can get some.


      • I am interested in a 2×12 adapter for my Walther Lever Action also. I checked everywhere I could think of without success. Does anyone know how to obtain one?

      • B.B.

        Here’s today’s shot tally. Using the Air Venturi 3.20 oz / 90 g CO2 in the Walther Lever Action rifle, I got a total of 504 shots. I quit shooting when the pellets were hitting about 3 to 4 mil dots below my aim point. Total time to load magazines and shoot: 3 3/4 hours. As I mentioned before, the Walther 88 g CO2 gave me 522 shots. I thought I would get more from the Air Venturi, but maybe it wasn’t really filled to the label claim of 90 g CO2.

          • B.B.

            I thought as much about the variability of the fill amount. Much as I enjoy the Walther rifle, I don’t want to have to shoot 500 shots every time I load and shoot it. I hope you and someone at Pyramyd AIR are successful in persuading Umarex to sell those 2X12 g CO2 adapters here in the U.S. Although you may think leaving the gun pressurized overnight or even a few days, in light of how much I’ve invested in my air guns, I’d rather err on the side of caution and make sure I consume and remove the CO2 the same day I install it.

    • I can’t remember where I saw that adapter, but looking up 2240 parts I saw that mixed in. It might be orderable online. I hate to have forgotten if the site was in pounds sterling, but may have been.

      • RifledDNA,

        I’ve done one Google search after another and not found a 2X12 g in-line CO2 adapter for the Walter Lever Action rifle anywhere. The only picture I’ve seen of one was in Tim Smith’s review of the Walther Lever Action rifle that he published in Airgun Hobbyist Magazine, Vol. 3, No. 4, Oct-Nov-Dec 2013. In that review, he says they are available only in Europe.

    • Charles,
      Have you tried your Hammerli 850 2x12g CO2 adapter in the Walther? When I called Umarex they said it would not work. I’ve read on the internet were some people say it works and some say it won’t. The threads have to be the same, but the length may be the problem. One article says you can grind material out of the butt stock to make it fit.

      • Kansas Heat,

        As a matter of fact I have successfully used the Hammerli 850 adapter in the Walther Lever Action rifle. The threads are the same as any 88 g/90 g CO2, and the adapter diameter is actually smaller than the diameter of the 88 g CO2. The problem is the 850 adapter is too long. The butt cap can’t be reattached to the rifle stock when the 850 adapter is installed. Pyramyd AIR posted my pictures showing this problem. Click the link to see my pictures. The Hammerli 850 adapter in the Walter Lever Action rifle gave me about 120 total shots.


  8. Just goes to show you, if you live long enough, all the mysteries of life will be eventually answered.
    In the early ’90s, I bought an (apparently) remaindered Tau Brno target pistol, mostly because I admired its swoopy, Buck Rodgers look and the sub-200-buck-a-roos pricing. Imagine my surprise when I got a kit complete with a package of spare parts to include a supply of “spare special seals”…what you or I would call “O rings.
    Now imagine my even bigger surprise when I learned the pistol could easily stack one pellet on top of the last, if I were to do my part in the process. To put is slightly differently, the pistol was and remains a far better shot than I.
    Bit here’s the mystery. With the inclusion of the extra seals, the inference was that the seals would need replacement often and on a regular basis.
    Now let’s see, that was almost 24 years ago…and I’m still on the original seals that came installed in the gun.
    Not knowing any better, I cheerfully have stored the Tau-Brno with a charged CO2 system for(sometimes) several years between uses and the next time I take it in my head to get a little practice in, it always shows a pressure level at a considerably more than usable level.
    The mystery is…”Why?” How come volley-balls, tennis-balls, bicycle tires, at least one gas revolver and about anything else tasked with retaining pressurized gas slowly leaks down and needs topping off the next time its used?
    Except the Tau-Brno?
    Thanks to B.B. pointing out the differences in both the systems themselves and the engineered sealing strategies, yet another mystery of life explained.

    I can offer a pretty valuable tip on long(er) term storage of things like neoprene seals, O-rings, and certain types of chemistry subject to oxidation. This comes from a long-term experience in photography where oxidation is never not a problem. The aforementioned O-rings and seals are stored in containers that can be themselves sealed, such as the plastic film-containers (remember those?,) sushi lunch-boxes, or even screw-top jars. Before sealing them up for storage in the back shelf of the refrigerator (Don’t freeze,) crack the lid/cap, slip the skinny red tube from your “canned-air” and displace the oxygen bearing air with a healthy squirt, and then snap the lid closed immediately. (“Canned-air has no air in it, is usually some variation of Freon or O2 free gas, and won’t oxidize otherwise susceptible items.) If the container is opened later on, don’t forget to re-do the “canned-air” thing.
    Also, don’t forget to label whatever is in there. It won’t do to go looking for 9 volt batteries or something and have to open all the sushi lunch-boxes to find them:)

    Now, on to that dropped-toast-jam-side-always-down mystery:)

  9. I forgot to mention, Happy memorial day! I know a number of members here have mentioned their service in Americas military’s, and I want to honor and thank you for your time and hard work. You all are close to the only honorable men this country knows, and it is not forgotten.

  10. The 1077 was one of the guns my daughters learned to shoot with. I cut about 3 inches off the butt of the stock so they could hold the gun better. Nice little light gun.

    And I wish I would of got one of those 88 gram adapters when they sold them. That’s one of the things that I don’t like about the cartridges. No way to stop the flow like the 88 gram adapter for the 1077. I wonder why that adapter is not available anymore?

    And I guess the co2 cartridges serve there purpose with different applications but they ain’t no fun in the Midwest winters when shooting outside. The only co2 gun that we have now is the Steel Storm. I have for some reason kept that gun throughout time. But I think I will have to say that I like the other power sources more. Just me you know everybody has their own likes.

    And thank you all who have served in the forces. And to the memories of the ones that have passed on.

    And we have some family and friends coming over today. So gonna get some shoot’n in today I’m sure. So everybody have a good and safe holiday.

  11. B.B,
    I have a dumb question. In your article “Ed Schultz, … told me that some of the modern seal materials can take a set if left pressurized too long.” What does “take a set” means?

    • Joe,

      It means to settle in one position and not spring back when tension is relieved. Carpet takes a set when furniture sits on it a long time and is then moved. You can see the depressions for a long time afterward.


  12. B.B.,
    In your article you said “My vintage CO2 guns, on the other hand, are always charged and never leak. They are like PCP guns, in that respect.”

    I would think the opposite is true, that the PCP guns leaks gas and the co2 unlikely, because I thought co2 molecules are larger than air molecules. So why PCP doesn’t leak?

  13. Wow ! I moved last September..like 2013…and my green colored stock Crosman 1077 is in its silicon sock…..still charged ! Can I shoot it without the magazine, in my cottage ? Being in Old Town Orcutt, California, the county does not allow anything other than AirSoft outside and allows anything inside “That does not penetrate a wall..”
    Thanks All !

  14. Thanks to all our veterans.

    I had thought that it was good to leave a CO2 gun charged, or at least not harmful. Anyway, it’s been so long since I’ve fired my CO2 guns, I’ll have a chance to put this to the test.


  15. Yes, my dad served in WWI in the calvary with his Indian Motorcycle as a messenger. Never went ‘over there’ thank goodness. My two brothers served in WWII, one as a skipper of aYTL (Yard Tug Little) in Hawaii, post 12/07/41 and my oldest brother as a Sergeant in the Army Air Corp, one of the managers of the PX on Guam. I severed during Korea War in Fr.Morocco as an Air Policeman, driving the base Brig. Gen. W.Hardy.
    Thanks, I’ll leave my Green Hornet Cr.1077 charged.
    Old Town Orcutt, California

  16. B.B.,

    In my younger days, I worked several years at my friends commercial paintball field. Because so many of the paintball markers at that time ran on bulk CO2, I quickly learned a lot about what to do and not to do when using CO2. I can think of a few tips that might help your readers.

    Minimize the amount of liquid CO2 that enters your gun, especially where it can come in direct contact with a seal in its path of travel through the gun. The liquid CO2 can permanently deform a seal because CO2 in its liquid form is extremely cold. The longer the length of this exposure the more likely the seal might be damaged. When you fire a gun, especially if it has a small CO2 source (12 gram cartridge) there will be a small amount of liquid CO2 that leaves the storage cylinder, however as it passes through the gun and out the barrel it turns to gas very quickly, and therefore will not hurt any seals it passes over. On the other hand, if you have the ability to fire a CO2 gun continuously without having to reload (as paintball guns can that have bulk ammo hoppers), you can literally fire the gun until it “locks up” the valve with freezing condensation (esp. in cold ambient conditions). I have both seen and experienced this myself firsthand. This lengthy exposure to very cold conditions inside the gun can damage the seals.

    Reguarding airgunners, this can come into play in less extreme ways. If you have a gun that uses an 88 gram cylinder or larger (paintball tank) and you choose to leave the tank on the gun, orient the gun during storage so that the liquid CO2 in the tank will be in the bottom of the tank, and not where it can run down into the gun and be right up against or right next to a seal. Also, when you are attaching or taking off your CO2 source, there can often be some blowby when doing this. Do what you can to minimize this blowby. 95% of the time that is liquid CO2 blowing right by a seal. If it’s a screw on connection, do it quickly to minimize that blowby. If it is piercing a 12 gram cartridge, to it quickly for the same reason. And don’t forget the drop of Pellgun oil.

    One last tip, don’t leave a charged gun in the direct sunlight for too long, esp. in hot ambient temps. This will have the reverse effect of excessive pressures building inside your gun. A mild case of this would be a hot (unusually fast) first shot out of your gun. A worse case would be partial valve lock (too much pressure on the storage side of the valve). And a very bad case would be a blown burst disc which are on larger CO2 tanks.

    I’m sure that B.B. has gone over most, if not all of this info before. But since we’re on the subject I thought I might revisit it.

    David H

    • CO2 in liquid form will be the same temperature as the ambient, if it hasn’t been used.

      It is the transition from liquid to gas that absorbs heat, producing the cold.

      If being cold was an innate attribute of liquid CO2, you’d have to scrape the frost off of the cartridges everytime you picked one up from the box.

      Liquid Oxygen and Liquid Nitrogen are innately cold as they don’t liquify at room temperature — they have to be cooled to even create the liquid form; CO2 liquifies at around 800-900 PSI even at room temperature.

      • Wulfraed,

        Yes, you are exactly right. And as I was reading you post, I thought to myself that I knew all this too. It’s been so long since I’ve needed to explain this that the thoughts in my brain and typing my thoughts out didn’t coincide. Thanks for the corrections. After all, it’s easier to do and get things right when you have all your facts straight.

        David H

  17. Went out with my brother for 100 rounds of 9mm from his Sig p239, awesome little gun. You get used to the airguns and it sure is a surprise when you get the powder poppin’ again.

  18. Jerry,

    I’m glad you did such a complete and thorough job. That was a lesson in what not to do and how to recover from it.

    No, I think you can now just shoot the rifle and the pellets will clean it as you go.

    Isn’t it great to get back on the road after a thing like this?


  19. B.B.
    I’ve been lurking in your forum for some time and have learned a lot about air guns and shooting in general. I appreciate your knowledge and tips.

    This article about CO2 is timely for me because I’ve ordered a .177 2400KT Carbine with a Lothar Walther barrel from the Crosman Custom Shop and have been impatiently waiting for its arrival for two and a half weeks now. I know they say to expect 3 to 6 weeks for delivery. I hope this one does come on the shorter end of that time period.

    My question has to do with converting a pistol like a Crosman 2240 from a 12 Gram CO2 cartridge to a bulk fill gun. I’ve been reading about the PowerMax Hipac (http://www.powermax-hipac.com/Pages/default.aspx) on the Internet.

    It seems like an inexpensive ($65), simple conversion that can easily be removed to switch back to the 12 gm cartridge if desired.

    I’ve gone back and searched your previous articles looking to see if you’ve written anything about this topic or this type of customization. I didn’t find anything so I’m wondering about this conversion and would like to hear your thoughts on it.

    Is it safe?

    Does it work?

    More useful shots? Less useful shots?

    Maybe one of your test reports on it would interest a lot of your readers. I know I would love to see that.

    At any rate, depending on your comments, I would consider buying a 2240 just for this conversion. I already have a 20 lb CO2 cylinder I use for Homebrew beer. I’m thinking I could use that to fill a paintball tank which my son has abandoned and then use the paintball tank to fill the gun.

    Look forward to yur thoughts on this topic.


    • 12 Gauge,

      This is the first I have heard about this conversion. I scanned their website and it appears they have done their homework.

      Is it safe? I don’t know. What do they say? They are liable for all safety issues with this product, but I have found that small operations often don’t carry any insurance and are just relying on luck to get them by. I don’t know if that is the case here, but I do know the insurance tab for a product like this would be astonishingly high.

      I could say many things at this point, but since I know nothing about this product, it wouldn’t be fair to anyone. I will say this, though. They talk about staying at 2,000 psi, and that would be safer than going up to 3,000 psi.

      Since you seem to want to do this, how about a guest blog? You could start with just the custom pistol the way Crosman shipped it.

      Welcome to the blog,


  20. B.B.,

    I’ll think about the guest Blog for the custom pistol. That might be kind of fun. I’ve read enough of your reports to know what seems to be of the most interest to your readers and what should be included to fully test the gun. I think I could do a reasonably good job of it.

    As to the Hipac conversion, I would like to do it, mainly because it seems like a very cheap way to get in to PCP, something I have been longing to do, but can’t seem to justify the spend. However the safety factor is a concern.

    Cheap could be another word for disaster. That’s why I was thinking of doing it for CO2. My thinking is that it would be safer, but I could be wrong on that as well. At any rate, it looks like it could be promising.

    Maybe some of your readers have had some exposure to the product and would care to comment?

    If I decide to do the guest Blog on the Custom Crosman, what is the process to submit that to you?

    Thanks again,


  21. I have been buying 12gram cartridges for my pellet pistols for yrs. But a few yrs ago I noticed the CO2 didn’t last beyond a day where as the old cartridges lasted weeks, without firing. I have a new Crossman 1088 and buy Crossman powerlet 12g cartridges. I can actually hear the C02 escaping after I tighten canister in. It is empty by the end of the day, shot or no shot. I read in this forum about sealing the cartridge, or even taking it out after use.. How does this stop CO2 from coming out the punctured head? Appreciate any help, a 5 pack of cartridges is expensive for 5 to 10 shots. I really only use it to drive the crows away from songbird nests around the property.

    • Welcome to the blog.

      I hope when you scare birds that you don’t shoot projectiles at them, because they can penetrate the skin and create festering wounds that can make the animal die a slow and painful death.

      Are you putting a drop of Crosman Pellgunoil on the tip of each new CO2 cartridge before you pierce it? If not, do so and your gun will be fixed.

      You cannot remove a CO2 cartridge from your gun without losing all the gas. Don’t try because you can get a bad frostbite from the cold gas.Your 1088 should give you a good 40-60 shots before the gas runs out. If you use Pellgunoil the gun will hold gas for months.

      Until you can buy some Pellgunoil, it is okay to use 20- or 30-weight motor oil, as long as it is non-detergent.


  22. BB,

    I love when you talk about firearms. I learned English by reading my dad’s old American Hunter magazines back when I was a boy. I wish I lived in a country where firearms were less expensive.
    I have a question regarding my new Walther CP88. How long to keep the co2 bottle?
    Thank you!

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