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How to convert from CO2 to air

Guest blogger
Converting CO2 guns to high-pressure air is becoming more and more popular, and .22 multi-shot has written a guest blog about converting his RWS 850 AirMagnum, which is a common conversion.

If you’d like to write a post for this blog, please email me at blogger@pyramydair.com.

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How to convert from CO2 to air
by .22 multi-shot

Why would anyone want to convert from CO2 to air? Well, I found out after purchasing a .22 caliber RWS 850 AirMagnum. It was everything I thought I would want – nice looking, good quality, reasonably priced and PCP features (many shots from one CO2 AirSource cartridge, 8-shot repeater). What else could you want? I ended up not fully satisfied. I wanted more power, and the power decreased more than I expected in cool weather.

Simplest conversion
I did like my RWS 850 and noted from B.B.’s blog that air has some advantages over CO2. So, I decided to try a CO2 to air conversion. There are couple of simple ways to convert a CO2 gun to air. The easiest is to use a paintball remote setup to connect an HPA tank to your airgun (see glossary below for definition of paintball terms). This is the setup I started with. I bought a paintball remote, HPA tank and AirSource-to-ASA adapter.

The AirSource-to-ASA adapter is the key to converting any airgun that uses an AirSource tank. It’s often called an AirSource-to-paintball adapter and screws into the gun in place of an 88-gram AirSource cartridge. The other side of the adapter is a standard paintball ASA. A paintball remote can attach directly to the ASA side of this adapter.

Glossary of paintball terms used

    • ASA: Air Source adapter. This is a connector with a standardized CO2 bottle thread that an HPA or CO2 tank screws into. An ASA has nothing to do with the 88-gram CO2 AirSource.
    • HPA: High-pressure air. High-pressure air or nitrogen that’s used for a marker instead of CO2. The tank typically holds pressures of 3000 or 4500 PSI. An HPA tank needs a regulator to reduce the pressure of the air that feeds into a marker. Most tanks are sold with a regulator.
    • Macroline: A type of plastic line used for paintball air connections.
    • Marker: Term used for a paintball “gun.”
    • Rail: A rail that an ASA can be attached to.
  • Remote: A hose with fittings that lets the air tank be remote from the gun. The hose may be a coiled or stainless steel.


Cooper-T AirSource-to-ASA adapter.


Paintball remote with AirSource-to-ASA adapter attached. The HPA tank screws into the black ASA on the left. The AirSource-to-ASA adapter screws into the RWS 850. Sorry, I don’t have a picture of the whole setup. I couldn’t find my paintball remote to take another picture.

Test results
The conversion using the paintball remote was tested using JSB Exact Jumbo pellets. Pellet speed ranged from 591 fps up to 602 fps. The average was 594 fps (12.38 foot-pounds). That makes this conversion equivalent to using CO2 on an 80-90F degree day. The HPA tank I used had a regulator with an output pressure of about 800 PSI. One advantage of this setup is that it’ll give you the same power even when it’s colder.

Going further
I’m sure some of you will want to go further, like I did. I didn’t like the remote setup because it was clumsy, so I worked on putting together a setup that’s part of the gun. The pictures below show two other setups I built. The last setup in these pictures will be my permanent setup along with other modifications. Some other things you can do:

  1. Use a regulator that has a higher output pressure.
  2. Use a heavier hammer spring. This will knock the valve open further.
  3. Use a lighter valve spring. This won’t push the valve closed as fast.
  4. Enlarge/polish some of the valve openings. This will allow the air to flow better.

Be careful. There can be side effects from these modifications. If you go too far, you might run into valve lock or the valve stem might bottom out when the hammer strikes. The valve of a CO2 gun is designed for CO2, so there will be limitations on what it can do.

Below are some pictures of different setups and the parts used.


HPA setup with Smart Parts Max Flow Inline adjustable tank regulator. This setup connects via macroline to a complex adapter with a bleed valve. The tank is a 3000 PSI, 13 cubic inch tank. I discarded this design. I didn’t like the look, and it was too complicated.


Tank mount made out of scope mounts from an inexpensive Daisy scope. The bottoms were cut off, drilled and threaded, then a paintball rail was screwed into them. I later discovered that 1/2″ PVC conduit fits nicely over the RWS 850’s barrel, and the scope mounts fit over the conduit. The reddish stuff is rubber gasket material.


The HPA setup with screw-in style Nitro Duck X-Stream adjustable tank regulator attached to a System X On/Off ASA. This is connected to the RWS 850 through a homemade quick-disconnect-to-AirSource adapter. For this style of setup, the ASA needs 1/8 NPT output port opposite where the tank screws in. The tank is a 3000 PSI, 1.5 cubic foot scuba tank. This is the style I’ll use for my final setup. The stock cap will be modified to hide the regulator and ASA, and the tank will stick out.


Homemade AirSource-to-quick-disconnect adapter. That thing sticking out the side is an 1800 PSI burst disk. Don’t copy this design. The hole isn’t deep enough for the burst disk to screw in and seal well.


Final setup plan drawings.


Key part for the setup above if you use standard parts. This screws into the AirSource-to-ASA adapter and makes it an AirSource-to-quick-disconnect adapter. Different stores have different names for it. Some of the names I’ve run into are C/A-to-1/8″ NPT, C/A-to-1/8″ plug, ASA-to-hose and ASA-to-remote.

Think before acting!
If you want the features of a PCP (pre-charged pneumatic) airgun but are trying to save money by buying a CO2 gun, just buy the PCP rifle! You’ll save money in the long run and will probably be more satisfied. If money’s an issue, check out the Benjamin Discovery. It’s very reasonably priced, especially bundled with the hand pump.

Here’s an idea of the cost of some tools you probably would end up buying if you get very deep into modifying your airgun. You may not need all these tools immediately, but they’ll add up bit-by-bit!

  • $100+ taps and dies
  • $100+ drill bits
  • $100+ belt/disc sander
  • $200+ floor drill press (used vs new)
  • $70+ portable metal band saw
  • $??? books
  • $400+ metal lathe and tooling (this can replace most of the taps and dies if you buy a lathe that can cut threads; it also can replace some of the drill bits)

Remember, be safe. Working with high-pressure air can be dangerous. It can kill you!

When I started work on this project, sources for AirSource-to-ASA adapters and small HPA tanks were difficult to find. Below are some other modding resources.

General info
Dennis Quackenbush (basic airgun materials)

Small HPA tanks
Wevo Paintball
JDS Air Man

Paintball parts
Palmer’s Pursuit Shop
Action Village
SAKWorld Paintball

AirSource-to-ASA adapters & other parts
Bryan and Associates
Mac1 Airgun Distributors
Crooked Barn
Mountain Air Custom Airguns

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.

66 thoughts on “How to convert from CO2 to air”

  1. Hey .22 multi-shot,
    Great Blog! I am not finished with my 2250 HPA conversion yet – I got sidetracked with building a 'chicken plucker'.

    The 2250 has an airtube that is burst rated by Crosman at 1800 PSI (according to the vendor that made my bulk fill adapter). I was a bit worried about feeding directly into this airtube with HPA. (Did not want to blow myself up.) Found a reasonable answer with some adapters that are rated right in the ballpark for the 2250 airtube: 1200 PSI, 1400 PSI & 1600 PSI.


    I will be trying to bump the Crosman 2250 past any low pressure valve lock up to accepting 1400 PSI with different hammer spring & valve spring combinations – though my dealer has told me the valve I bought from him should work at those pressures. (Bulk Fill "Boss" Valve). We'll find out after this 'chicken plucker' is finished.

  2. Great blog multishot, however it is worth mentioning that there are other ways to convert an 850 with ready made parts, with minimal of your own fabrication, so the cost savings would be significant. Also, it is you can get more velocity out of the gun than mentioned in the blog. Following is the link to my converted 850, which was shooting 700 fps in .22



  3. How about a maintenance blog?
    I think it would be great (it would certainly help me…).
    What should we do when storing our airguns? How many pumps for a multi-pump between usage, how about single pump guns? How much oil, what kind, where?
    When and how to properly clean the barrel?
    Are quick cleaning pellets any good?
    By now we all know to put a drop of pellgunoil on CO2 guns, but how about PCP’s?



  4. .22multishot

    Good morning,

    Nicely done….

    With the gun and parts, and without the tools, how much did it cost? and then if you add $20 per hour for the actual time to convert, not the research time.. how much would it cost…

    The bottom line question is; on a small scale how much would it cost to convert 10 at a time? and would it be worth it?


    Ashland Air Rifle Range

  5. Wonder Boy. Converting will actually end up being cheaper when you take into consideration that you will end up with a REGULATED gun that will give you FPS consistency and also in case of 850 – an 8-shot repeater. You could not touch such a pcp for the conversion money.


  6. I too have an 850 AirMag, and I have converted many co2 paintball markers to HPA. Its kinda strange but I was talking to a guy at work today (I work 11pm-7am), about the benefits of converting his paintball gun to HPA. I know that converting paintball markers is rather easy because all of the fittings are the same, the valves on are huge, and pressure and airflow is adjustable. I was thinking of converting a cot rifle to HPA but I’m so happy with my 850 that I don’t want to mess with it. If I do attempt this, it will probably be with a cheaper Crosman gun.

    It’s nice to see that you got some parts from Palmer’s. The guys there are nice, and their products are very high end. In fact, Palmer’s is the only company that makes a high output secondary pressure regulator rated for both co2 and air, that I can think of.

  7. I just noticed that you mentioned Wevo Paintball. Those guys are great. I was going to have them build me a custom stock class CCI Phantom but unfortunately I had to cancel my order due to a shake-up at work and concern about potential lay-offs. This economy sucks.

  8. nitr0_fish,

    Thank you! I have parts for converting my 2300KT (Crosman custom 2240) to air. I’m waiting to finish my RWS 850 though (I’m working on a new valve).

    I bought a Discovery tube since I couldn’t get an answer about the working pressure for the 2260 tube I bought. I was fortunate because Crosman has stopped sales of Discovery parts until next year. Their policy is not to sell new gun parts until a year after the gun is released.

    .22 multi-shot

  9. Chris,

    Thank you! Yes, there are other ways to convert. I just talked about conversions that I’ve done.

    I went to your link to see your conversion, unfortunately I can’t seem to see the pictures!

    I probably should have mentioned that you don’t need the ASA in the last conversion. You can just screw the tank into the AirSource-to-ASA adapter. I used an On/Off ASA in my setup so I can turn the air off and leave it on the gun or remove the tank. With a setup like this, I can create a locking mechanism so my kids can’t turn the air on and have an accident.

    .22 multi-shot

  10. Wayne,

    Thanks! Yep, a big problem with converting is all the research and cost for multiple setups if you aren’t satisfied!

    When I purchased my 850, it was $240. The price has dropped to $216 now! The parts for the last setup cost in the neighborhood of $200 (using an On/Off ASA).

    I would have a hard time estimating time. Your first setup will take the most time (finding the exact parts to use, etc.). If you don’t have to make a mount, it will take you 5 minutes to put together. Otherwise it will probably take half an hour or so(depending on your tools).

    Wish I lived near you so I could try out your range!

    .22 multi-shot

  11. .22 multi-shot

    Thanks, so possibly around $500 or so if one was paying labor…

    How loud is it now? compared to a discovery or something we know..

    It’s seems pretty hard to compete with something like the AR6 for $600 that shoots 1315 in .22 cal….

    Move to Southern Oregon, and start enjoying life… the economy sucks everywhere… don’t you remember about that “sucking sound as our jobs went out of the country” What ever happened to him anyway.. I loved his charts and all…

    Start a small business online, if you want to survive…. it’s not that hard.. just find the right niche…

    We might get a cash flow going in the Rifle range and you can make money working with air guns… who knows….


  12. J-F,

    Believe me, it’s all there right now. This blog is like a public library and you have asked to see articles from many different books.

    What you have to do it learn to use the search function to find what you are looking for.


  13. BB, Been a while since my last blog. I’ve an off-topic question here. My most recent purchase has been a RWS Diana 34 T-05 from PA. I went ahead and bought the ‘new’ Leapers droop comp. mount for it. After mounting the new rail, I noticed that the front plate/block of the mount wouldn’t sit flush with the top of the action. So after reading the instructions and the back cover, where it clearly states that the locking plate is reversable (11 mil. or 3/8″)it isn’t. Upon inspection, there’s no way this is possible, so I removed the locking plate, sawed about 1/2″ off the long end thinking the plate would work then,…Buuut, the allen bolt holes didn’t align either. Has anyone else noticed that the plate is not reversable? I went back and studied the inst/packaging again, and the only thing that comes to mind is that the whole rail assembly can be mounted backwards. This kind of defeats the purpose of the droop compensation value, and the recoil block meant for the front of the factory rail. Has Leapers QC been made aware of this?!? What are your thoughts on this? Thomas

  14. Good, that answers my last theory. I was pretty sure the whole mount wasn’t reversable. Not very conducive to solving the droop issue!!! LOL’s…but the locking plate is ‘not’ reversible. That’s the part I was referring too,…where the allen heads tighten to the weaver rail. The back of the packaging says it is. I’d send pix, but don’t know how to post them on here. Thomas

  15. .22 multi-shot,

    I am impressed as ever with those who can fix and modify their airguns. I have heard a criticism that the RWS 850 leaks CO2. Did you find this to be a problem and did the air conversion fix it?

    All, just back from Berlin. Quite a place. I asked about airgunning but the people I was with did not participate although they said it is popular. I also saw some very fine pieces in the historical museum including a wartime 98 Mauser with what looked like a tiny scout style scope placed far forward on the rifle. I do believe that optics have come a long way even if the basic gun technology is the same. Museum films showed huge stacks of Mausers surrendered at the end of the fighting. How nice to have been on hand to pick one up although perhaps not with all of the bullet holes all over the buildings.

    I also watched the Olympics and heard about the Chinese gold medal winner who had to give back his medal because he was detected using beta blockers to steady his hand. I don’t know if you’ve discussed this in last week’s blogs which I haven’t looked at yet. I may put in a prescription….heh heh.


  16. Hello .22 multi-shot,
    Nice blog. I like your realistic accounting on just how much money you can dump into tools and equipment on fun projects like these!

    You mentioned safety in your blog, and I’d just like to add my 2 cents.
    CO2 is usually in the 900-1,000 psi range, although a full tank can reach close to 2,000psi in a hot car. I would hope that most CO2 guns are made to safely handle that kind of pressure. I also hope no one tries to run their CO2 gun from an unregulated high pressure air tank. You never know what the design safety factor is and 3,000 or 4,000psi might prove very dangerous. Anywhere from a leak or valve lock, to an explosion. Most paintball HPA tanks have built in regulators that, for safety reasons, throttle their output to approximately the same pressure a room temp CO2.
    Again, Good Job!

  17. I need to let everyone know what the reference to “Dennis Quackenbush (basic airgun materials)” is. I was referring to the link on Dennis’s web site called “Steel for Airguns”. This talks about the materials he uses in his airguns plus some other tips.

    .22 multi-shot

  18. Mechredd,

    I had to mention Palmer’s and Wevo! Wevo was the first place I saw small HPA tanks generally available and Palmer’s has a lot of parts that allow you to cobble just about anything together (and they seem to care about quality).

    .22 multi-shot

  19. B.B.,

    Thank you!

    I wanted to let everyone know what kind of work you and your wife, Edith, do with our guest blogs. To experience the professional editing job you two do is a pleasure! I even noticed you did a little editing on the pictures!

    Thanks again!
    .22 multi-shot

  20. Wayne,

    Yes, $500 is probably about right. Remember, that doesn’t include modifications to improve power.

    The converted RWS 850 is similar in loudness to its pre-conversion state (a bit louder). The closest other gun I can compare it too is a Crosman 2300KT (custom 2240) since everything else I have shot is quieter (springers, 1377, Walther PPK/S BB gun).

    .22 multi-shot

  21. Matt61,

    Yes, I have heard that some 850’s had a problem with leaking CO2. I did not have that problem with mine.

    I read on one forum that someone who had this problem discovered that it was caused by the threads of the AirSource cartridge cutting into the o-ring in the valve. This seems logical. The Crosman AirSource has a shorter smooth section before the threads than some other manufacturers. If you were careful not to screw it in too far, it wasn’t a problem.

    I noticed that RWS changed a few small details in their valve design (I have my original valve and bought a couple of new valves, so I compared them). It is possible that some other leak problems have been addressed by these changes.

    I have not had this problem with my conversion either.

    .22 multi-shot

  22. Lloyd,

    Thank you. Also thanks to re-checking the cost section because of your comment, I discovered a mistake. I put a comment, “(used vs new)”, at the end of the drill press line. I orignally had a used price/new price and didn’t remove the comment when I removed the used price.

    I want to make sure people think about where this can lead too! I didn’t. I don’t regret the experience and knowledge I’ve gained, but I would have made some different choices if I had known more. For instance, I would have bought a lathe. Most of the money I’ve spent in drill bits, dies and belt/disc sander could have been applied to a lathe. A lathe can do most of the same things by boring, cutting threads and facing! Lathe prices have also gone up about $100 since last year!

    Nick Carter, if you read this, I have my eye on a Taig lathe! I also might try to convert my little 8×12 wood lathe to a metal lathe.

    .22 multi-shot

  23. B.B.& .22 Multi-Shot,
    I also place my 850 at the top of the enjoyment heap of my air rifles, due to 1.)8-shot capacity; 2.)light weight composite material; 3.) More than 240 shots per 88 gram CO2 cartridge; 4.) Price; and 5.) adequate accuracy considering it is an "under $222 multi-shot" air rifle [lots of competition here:)].

    Now changing the topic temporarily, I want you to know that during the winter I shoot from my 45 degree unheated garage and outside for up to 40 minutes when it is around 35 degrees. In preparation, I have my Condor CO2 tank stored in a dust free container in the furnace room, which in the winter is always 80-90 degrees [cannot get hotter]. The tank is wrapped by 2, 9-volt battery operated heated socks, wrapped by a cotton athletic sock (primarily for comfort and perhaps to keep the warmth in) – about 1 hour before shooting I connect the batteries in the sox. This keeps the gun shooting strong for the whole 40 minutes outside or for at least 3 1/2 hours in the windless 45 degree garage.

    Returning to the topic of the day, the point of this is that you may be able to adapt this sock technology to the 850. I also store my 850 in the furnace room, and because I have not had problems with a cooling CO2 tank here in the cold weather (I have not pushed it much), I have not needed to use the heated sock idea. Because the CO2 tank resides in a contained, wind-free environment, the heat may be expected to stay so long that you probably will shoot very strong for at least an hour and thus will not have to make any more conversions.

    My question for B.B., related to all this. Why does my Condor shoot at 10 yards on HPA (about 800-940 fps at 10 yards) pellet on pellet accurately, whereas when I change to CO2 (about 550 fps at 10 yards) the 10 yard groups fall off noticeably, no matter what type of .25 pellet? P.S. Please do not simply say "this is a hunting gun, it was designed to shoot over 800 fps, not 550 fps…silly wabbit!" And please do not refer me to the answer in one of those nice gun books that you sometimes suggest. Thank you. – Dr. G.

  24. Dr. G.,

    Wow – you really limited my responses!

    How about your CO2 valve isn’t functioning as smoothly as your air valve? Ever think about that?

    What can be done about it, assuming I’m right, is a valve tune – but that voids the warranty.

    Where does that leave you?

    Also – and this is big – .25 pellets are not made as well as .22s. Ain’t no way around that one. The more powerful gun may just be stabilizing them better than CO2.


  25. B.B.

    Short, not sweet, but perfect reply… I was wondering about the .25 cal vs .22 cal in a CO2.. trying to shoot .25 cal with CO2 seems a little silly to this novice… to me CO2 is married to .177 and I really never got excited about the low power marriage to high cost little tanks you throw away… so I never tried it and you guys know, not me…


    Ashland Air Rifle Range

  26. Here’s a question for BB and the group. I print most of the targets that I use – partly because I’m cheap, but mostly because I have a wide selection to choose from and like to print whatever I’m in the mood for without keeping extras on hand.

    Store-bought targets are printed on special paper with fibres that are “fatigued” (probably with some sort of bleach) so that the pellets make a nice clean hole. I don’t see this sort of (blank) paper at the office-supply store and have been experimenting with different types of thicker paper, but haven’t found a reasonably good alternative yet.

    I’d appreciate hearing from others about their favorite paper types for home-printed targets. I don’t expect to find an exact replacement for specialised target paper, but whatever comes closest to the nice clean holes I get with the Beeman targets I use sometimes.



  27. .22 Multi,

    Good blog…if I needed another project, I might try something similar. I was thinking a QB7x on HPA would be a good start, since repeating action doesn’t attract me that much, but the Discovery is so much easier and probably cheaper (as you point out with the section on project costs).

  28. B.B.,
    Regarding the decrease in accuracy of the Condor with CO2, since the lo-flo HPA valve produces velocities very similar to the CO2, and also very similar loose groups, I conclude that this rifle is simply made to operate most accurately at the higher velocities, independent of the propellant used. I imagine that many rifles lose accuracy when slowed down 35%. – Dr. G.

  29. .22 multi-shot,

    Interesting read. I have an 850 in .22 cal and enjoy the ease of use and multi-shot feature for plinking. I can understand the PCP attraction.

    Unfortunately, my 850 does not group well, so it was a favorite for a while, as all new arrivals are – but now sits in the darkest corner of my gun safe.

    I had a problem early on with the seals and had to send it in for service. The technician (Greg) blamed it on debris in the Crosman cylinders. I also put an aftermarket LDC on it, but the pellets hit the edge of it.

    This has not been a blessed rifle for me. I can’t help but contrast this to my R-1, which served me for over twenty years with nary a problem.

    Any tips for improving accuracy in the rifle? I think I have read of tuners for 850’s, but mostly for extra power and trigger work. (I tried taking off the front cover & and the scope on it is one of my best, more $ than the gun)


  30. Volvo,

    I’m sorry you’ve had problems with your 850! I’ve heard that some 850’s don’t group well while others are great. One possibility is a bad crown. I don’t know how much it would be to have it recrowned, but you could try that. Also, have you tried a variety of pellets to find which one groups best in your gun?

    .22 multi-shot

  31. Nick,

    Thanks! I’m debating whether to try the wood lathe conversion first or make the leap and get the Taig.

    It looks to me like an evaporative cooler motor would work well with the Taig, and they are readily available. Since they have two motor speeds (1725 and 1140 RPM), you get more speed combinations too!

    .22 multi-shot

  32. B.B. & .22 Multi-shot

    I think I received a dud. I followed some of the links from .22 Multi’s blog and it seems guys worship these rifles. It would be hard to believe that was the case if they all shot like mine. What makes it frustrating is it is such an easy gun to shoot.

    One of the tuners mentioned that sometimes the barrel needs shimmed to keep it tight.
    In addition to the initial cost of the rifle, I have spent $50 to send it to Texas and back, and $65.00 on an aftermarket piece that didn’t work.
    My quandary now is cut my losses and sell, or spend another $150 to see if it can be made “sweet”.

    As far as attempting the work myself, when I went to remove the ill fitting LDC, it was stuck on. So what began as an attempt to carefully remove and adjust ended with the LDC becoming scrape metal. Point being, I know my limitations.


  33. Wayne,

    I still have not pulled the trigger on the HW55-T. I know the price is right, but other factors weigh in. I have an HW97, HW50S and HW30S already, all of which are wonderfully tuned by PW.

    I also have self imposed limits on the numbers of firearms and airguns I possess, so I’m not sure the 55 T is “sponge worthy”. Without ever touching it, I know it will be a sweet shooter that is low in power for the weight of rifle. It is definitely a “looker” as well.
    However, thinking back to younger days gone by, even if you really love brunettes, a blonde is still a nice diversion once in awhile. (I’m speaking about the finish on the stock)

    So while I passed on the FWB 124 for the R-1 years ago, it will be something total new to me when it arrives.

    The other air rifle that captivated me but I never owned was in the ARH catalog. It was a Wischo, I never see much written on these so I’m not sure if they were any good or why they fell from favor. But at the time, they too had centerfold status. I have been keeping my eyes peeled, but have yet to see one on gunbroker.


  34. Volvo,

    Hermann Wilsker, the founder of the Wischo export company, had an office in Erlangen, the city in Germany where I lived for almost 4 years. A Wischo is really a BSF, so you read about one when you read my report on the BSF 55N.

    Just in case you hate your 55, remember, there are others who might feel differently and be willing to do something about it.


  35. B.B.

    I had read your blog first, but with all the buzz about them thought maybe you were a little too demanding, had a less than perfect specimen, or that I would not mind. Amazing how we can rationalize anything.

    I have decided maybe I pair it with a red dot sight that I also have no use for, and the two will complement each other? Looking down an 18X scope and watching pellets hit all around the crosshairs is goofy, but the red dot is inexact also, so a match made in heaven?

    I could make it a dedicated tin can type gun…..and spare myself possible future frustration. Accuracy aside, it is fun.


    BB – I double posted a reply to Wayne above, can you 86 it?

  36. 22 Multi shot & B.B.

    I need to recant my accuracy concerns on the RWS 850. After I received it back from Umarex, I shot a couple pellets over a chrony to make sure it was okay and that was it.
    Back to the corner of the safe.

    .22 Multi your blog and links brought out a renewed interest in it, and I exchanged the scope for a red dot and also added a laser sight that I had purchased some time ago and never even opened.

    Even with these relatively crude sighting devices, I was able to keep all 8 shoots nicely in the 10 ring of a Gamo target at 33’feet. Now, I realize these targets are way larger than actual 10 meter targets, but the gun could not even do this before.

    I’m not sure if Greg corrected some other opportunity while replacing the seals or the UPS man tossed the package just the right way, but it now shoots at an acceptable level for a $200 CO2 gun.


  37. BB,

    Isn’t the very act of replacing the spring, front and rear guides a type of tuning:)? I guess by no tuning you mean you didn’t polish or lubricate, just change parts. It would be hard to resist tweaking a few things after going to all the trouble to take the rifle down!

  38. The $3 dollar spring mod (swap out main psring with a $3 replacement) take 5 minutes and adds 80 to 100FPS to a .177 and 50 to 60 FPS in .22.

    I’ve done both my 850s and it the easiest, cheapest solution to make this gun a real pigeon killer!

  39. Scott,

    It can be a lot of time and effort.

    The 1250 Dominator wasn’t available when I bought my 850. However, I think the Dominator is overpriced since it appears to be an 850 with a few changes (e.g. hammer spring, valve and PCP tank). I would have bought the Discovery if it had been available at the time.

    .22 multi-shot

  40. I am looking for a PCP air rifle and am wondering of the quick connect valve from an air rifle tank are the same as the fitting from a 3000 PSI paintball tank. I have a paintball air tank and a sucba tank fill station already. If i can avoid buying these again that would be a nice savings. Also are all air rifle quick connects the same? I am looking at either the Discovery or an Airforce PCP. Thanks for the help.

  41. Ken,

    I can tell you that no standard paintball fittings will interchange with air rifle fittings. Over the past few years, however, the paintball crowd has been getting into Foster quick-disconnect fittings. That is what the Discovery has.

    AirForce guns use a proprietary fitting that no one else has, but Airhog can turn one into a male Foster quick-disconnect for you.



  42. OK – I've been googling but can't find the Cooper-T airsource to paintball adapter (i.e. shown above,allowing an 88gr airsource gun to hook to paintball remote/tank.

    Any ideas on what happened to Copper-T or where I can get such a thing these days?

  43. Robert,

    have you tried going to any of the sites mentioned at the very end of this Blog? Bryan and associates for one, may be able to make the converter you need. I don't know if they actually have the Cooper T adapter but they have a bunch of others that may suit your purpose. Here is their address, obtained from Google:


    Check out the other sites, as well.

    By the way, very few of us monitor these older blog comments. There is a core of volunteers, such as myself who do and try to help folks like you. If you'd like more help and more comments, I suggest you start leaving your comments on the most current blog. That can be found at


    A new blog appears MOnday through Friday. We look forward to you regularly visiting the blog and commenting, as you see fit. By all means, do read the older blogs as there is a significant wealth of information there. Just post comments on the current blog, even if it's off topic. They're welcome, as are you.

    Fred PRoNJ

  44. Hi!

    Can anyone tell me just how I can convert my CO2 powered semi-automatics and revolvers to PCP/Constant air pressure flow? Mini scuba tank, with size of a 20 gram CO2 cartridge perhaps? Can? you find any "special made" PCP cartridges the size of a standard 20 g CO2 cartridge?

    Please help. Temperature, weather and wind/elevation here in Scandinavia in so unpredictable, just about everywhere else. Especially here in the middle region of Norway (Region Midt/Midt-Norge/Trøndelag)!

  45. I'm posting this for Tommy,

    I saw the same setup on a GAMO PT-80 co2 pistol!!! All the guy did was make a sling for the tank and voila 🙂 Love this blog, You guys have taught me a lot..I'd rather just grab a factory ready PCP IMHO…Peace.


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