looking for help with a CO2 pellet gun problem

[frkelly74]

I bought a 177 CO2 gas pellet gun some years back. I used it some at first and found that it would kill rabbits if you shot them through the lungs. I hadn't touched it for probably 5 years until a few days ago when I got it out to shoot at some chipmunks and found that it would not fire. It is a Crossman with a wood stock that is set up to look like one of the 22's that they use in the bi-athalon in the olympics. It has a really well proportioned hardwood stock but has open sights which are not a big problem given the range limitations of the arm. So, the symptoms are ; with a new gas cylinder, that I have had since the gun was new, there is no immediate pressure available to propel the pellet. If you lay the gun down for an hour or so them there is pressure for one shot and the second will be about half pressure and for the third there is no pressure. lay it down again for an hour and this sequence repeats. Does CO2 have a shelf life? Is there something I need to do to loosen up the firing mechanism in the gun? anybody with experience please chime in. Thank You

[44man]

I bought a 177 CO2 gas pellet gun some years back. I used it some at first and found that it would kill rabbits if you shot them through the lungs. I hadn't touched it for probably 5 years until a few days ago when I got it out to shoot at some chipmunks and found that it would not fire. It is a Crossman with a wood stock that is set up to look like one of the 22's that they use in the bi-athalon in the olympics. It has a really well proportioned hardwood stock but has open sights which are not a big problem given the range limitations of the arm. So, the symptoms are ; with a new gas cylinder, that I have had since the gun was new, there is no immediate pressure available to propel the pellet. If you lay the gun down for an hour or so them there is pressure for one shot and the second will be about half pressure and for the third there is no pressure. lay it down again for an hour and this sequence repeats. Does CO2 have a shelf life? Is there something I need to do to loosen up the firing mechanism in the gun? anybody with experience please chime in. Thank You
There are no perfect seals and you might have lost the CO-2. Then the rubber seals in the gun can go bad by drying out.
If it uses one of the small gas cylinders, it could have been bad or leaked. Get new gas. Use pell gun oil to bring some stuff back.

[Bill*]

The cartridge should store practically forever till punctured for use. It sounds more to me like the feed line from cartridge to reservoir is clogged up or the "needle" that punctures the tube has been damaged and the tip closed up.

[44man]

The cartridge should store practically forever till punctured for use. It sounds more to me like the feed line from cartridge to reservoir is clogged up or the "needle" that punctures the tube has been damaged and the tip closed up.
I have had a new cartridge that was empty. I have also seen old guns that just dumped all the gas when the cap was punctured because of dry seals.
Some of the guns last forever if used a lot but but fail if stored. Even the pump up guns last better if used a lot.
Internal parts get gummed up and hardly move when you pull the trigger.

[frkelly74]

I sprayed CLP in the where you put the gas bottles and let it sit and got 5 shots before the no pressure symptoms showed up. So I laid it down to see if the pressure would build up or if the bottle is empty.

[44man]

Check the hammer that hits the valve. It might be sluggish.

[R.M.]

All very good suggestions.
I had one gun where the piercing punch actually sealed the hole in the powerlett. I relieved the punch so that it was smaller the further it entered the hole. Fixed it right up.

I don't think the CLP was a good idea. Petroleum products tend to degrade rubber o-rings. One should use synthetic only. Also, rubber o-rings absorb CO2 and swell up. Some of my target guns come with 2 end caps, so when changing, you replace it with the spare, rotate them to let the freshest one return to normal. You take the chance of cutting the o-ring if you reuse it right away while it's swollen.

[KCSO]

Right on there there is a special oil that you need to ue to keep the O rings up. The sad thing is that if you send it back to the factory they will re condition it for just about what it cost new.

[Jeff82]

Yep, sounds like bad seals. Crossman makes a product for pellet gun seals called PelGel. Get some of this and and put a few drops on the CO-2 cylinder nipple or your CO-2 intake. I've seen it do amazing things for pellet guns. If you are comfortable taking the gun apart, you can lube and inspect the seals with PelGel, or replace the seals as needed.

[frkelly74]

I am perfectly comfortable with taking it apart. It is only the putting it back together that is somewhat troubling. PelGel eh? I will have to look some up. Thank you.



PelGel brought up an explosives company in India.

[Silver Eagle]

Actually, it is called "PellGun Oil". To use, you place a drop on the tip of the CO2 Powerlet and insert it into the pistol like normal. The shots fired will distribute it to the seals and areas that need it. Most of the word on the web is that it is a blend of ATF Transmission fluid and 30wt non-detergent motor oil. In a pinch straight ATF works, just not a steady diet of it.
It sounds like the seals are leaking out the CO2. Inspect a used CO2 Powerlet and verify that the hole is cleanly pierced. Look in the area where the nose of the Powerlet goes and verify the piercing pin is clean and not clogged. Examine the sealing O-ring and make sure it is not cut or swelled up. If it looks questionable replace it. Look up the model number on the Crosman site and download and examine the internal diagram and parts list. Anything with a listing of o-ring or seal should be replaced. Crosman parts are generally inexpensive and if you give them a call and explain the issue, they may suggest the parts you need to rebuild it. You cannot order parts online, you must call them and speak to someone. There are generally a couple internal seals that should probably be replaced after sitting in storage and drying out.
Almost all airguns have been taken apart to modify or rebuild. A Google search will bring up either a video or instructions on how to disassemble, repair and, reassemble the pistol.
If you have been using gun oils to lubricate it, you might need to give it a good cleaning to get rid of the old lubes.

[frkelly74]

I have come to a conclusion in this little problem. I hunted around for the box and booklet that came with the gun and read through it. There was nothing very helpful in there either in English or Spanish. there were addresses of where to send the rifle in case of a malfunction and there was a disclaimer right at the end that said that if you do decide to disassemble the gun yourself then you will not be able to reassemble it yourself and there is no warranty coverage. I took this as a personal challenge to my reassembly prowess of course. There was also a statement about special tools and fixtures that are absolutely necessary to work on these guns. Well I got my old rusty screw driver and set to work disassembling my gun after first making sure the gas was out of it and there was no pellet in the chamber. It was really quite simple and came apart easily. Lo and behold, at the very heart of the valve seal is a tiny brass screen with a very fine mesh in it and don't you know it was all plugged up. so I cleaned it and started to reassemble. This is where the special tools and fixtures come in. The brass valve body slides way up into a steel tube and has to be oriented just right or none of the screws will thread back in and the passage for the gas to get to the chamber will not pass gas. So I made a special tool, see picture, it cost a dime and a short piece of dowel and worked flawlessly. The gun now functions as it should and the chipmunks better look out.