Pneumatic Pnews

Monday, May 29, 2006

CO2 techniques

by Tex Force

A lot of shooters find CO2 guns fun. There are a few tips and techniques, though, that can extend your fun and keep those guns working a lot longer.

Buy some Crosman Pellgunoil
This stuff works like magic and every airgunner who shoots a CO2 gun has a supply close by. It doesn't take much, but Crosman Pellgunoil helps your seals do their job a lot longer. In fact, if you use it regularly, a CO2 gun can last for decades - as long as it isn't abused in some way. Put a drop on the tip of every new powerlet or AirSource cylinder (bottom of the page) you load. Crosman says to oil every third powerlet or cylinder, but I have NEVER seen Pellgunoil do anything harmful to a gas gun. I use it every time.

What's a good substitute for Crosman Pellgunoil?
Well, here is what NOT to use: 3-in-1 Oil and other household light machine oils, which are too thin for this job. They will actually make your CO2 guns leak. WD-40 should never be used on any gun - air or firearm - for any reason. It dries to a varnish that gunks up the mechanism. Some shooters say automatic transmission fluid (ATF) can substitute for Pellgunoil, but why buy a quart of that when a small container of the right stuff costs very little? Besides ATF, there is very little that can reliably substitute for Pellgunoil.

Not too tight!
When installing a new powerlet or AirSource cylinder, tighten the screw that holds the powerlet or cylinder just enough to pierce the tank - and no tighter. If there is a leak, no amount of extra tightening will seal it. It's Pellgunoil that seals leaks, not pressure! The seals can do their job without the screw being tightened overly hard. The seal that seals the powerlet or AirSource cylinder is usually a thin synthetic membrane that compresses and tears if the screw is too tight. Better to oil the tip of the tank that abuts this seal and tighten only enough to pierce it. When you hear the gas flow into the gun, stop tightening!

Can you leave a gun charged?
This question comes up all the time. Modern Crosman owners' manuals tell you not to leave the guns charged, but this is often because of safety - like leaving a gun loaded, which a charged CO2 gun is, in effect. While removing gas cartridges may not present a problem for a powerlet user, when an AirSource cylinder has to be removed, it's an expense you don't like to incur. I just tested a Crosman NightStalker that has had a charged AirSource cylinder in it for six months, and it's still holding fine. I have been told by an airgunsmith that some pellet guns are made so that leaving them charged puts a strain on the gas system, so those guns would have a problem staying charged. I guess it's up to the owner to decide what to do, and lacking specific knowledge to the contrary it's always best to follow the instructions given by the manufacturer. If there are no instructions that tell you to remove the source of CO2, it's best to leave the gun charged to keep the seals fresh and protected from airborne dirt.

These are some of the basic care tips that can prolong the life of your CO2 guns.


  • Tex,
    my rifle has arrived and it is sweet. I took it out of the box cleaned it and shot away. When I mounted the scope and all it took was elavation movements.It is very accurate with RWS Super Holllws. Although I am a little disapointed because when I first chonyed it it was 800 FPS on average. Now it is around 620 FPS with the hollws and 600 with Crosman domes(quite accurate too). The manual says it will gain accuracy and velocity after apx. 2000 round. Did your gun do this? If you have any info let me know.Thanks,


    P.S. I havent found your problem yet.

    By Blogger sav300, at 7:42 PM, May 31, 2006  

  • Tex I forgot to ask, would you recomend a tune for this gun?


    By Blogger sav300, at 7:48 PM, May 31, 2006  

  • Tex,

    I have heared, that pellgunoil consist of pure silicone-oil. Is this right?

    Every mineral oil will dissolve the synthetic seals but WD-40 sounds like a good choose for surface protection because of its varnishing effect.


    By Anonymous Anonymous, at 3:41 AM, June 01, 2006  

  • sav300,

    My 99 is a .177. It shot in the 900s at first, but now it is in the 700s. I do know that corn oil (Wesson Oil) down the transfer port will increase the velocity.

    Yes, the gun will get slightly faster after many shots, but I wouldn't expect 200 f.p.s.


    By Anonymous Tex Force, at 5:42 AM, June 01, 2006  

  • How can a thin layer of "oil" provide an air tight seal between a seal and a high pressure gas source. I don't understand

    By Blogger D.B., at 12:04 PM, June 02, 2006  

  • D.B.

    Your car engine uses oil to lubricate the moving parts, to cool them and to seal the compression chambers when the fuel-air mix explodes. A film of oil between two close-fitting parts is one of the most effective gas pressure seals there is.

    The hand pumps that were used to pressurize vintage pneumatic airguns - those from 1600 to 1900 - had a plain steel or iron piston head running inside a steel or iron tube. Plain oil was used to seal this piston and these pumps can generate up to 1,000 psi.


    By Anonymous Tex Force, at 12:51 PM, June 02, 2006  

  • Markus,

    I would not use WD-40 on any gun. I once had to clean off the varnish left by it, and it took many hours of scrubbing.

    Yes, Pellgunoil is silicone, but how pure I'm not sure.


    By Blogger Tex Force, at 12:54 PM, June 02, 2006  

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