GasRam in Gamo CFX .22

GasRam in Gamo CFX .22

Joined: August 10th, 2007, 5:55 am

August 10th, 2007, 6:32 am #1

Apparently, the Theoben GasRam is not a straight fit for the CFX piston. I saw several pictures on the internet where people used tape to fit the gas strut into the piston.

This surprised me a bit. The piston is not moving relative to the gas strut. But it gets slammed each time a shot is fired. And due to the way the firing mechanism locks, each time the CFX is cocked the piston is bent a little bit (I did not open the CFX yet, so this is by reading on the Internet.

So I would guess after a while the tape will become compressed and allow play between the gas strut and the piston.

So how good is this tape trick?

I have access to a workshop who works up to the micron. And I was planning to make two rings instead of the tape. I was planning to make them in stainless steel, and a very tight fit. One would be screwed to the piston, the other would be kept in place by the front of the gar strut.

Is this a good idea? Or am I looking for too much trouble, and should I go for the tape solution.

Should I use another (lighter) material for the rings?

Instead of modifying the rear spring seat so it fits the gas strut, I'm going to make a new one, so I can still go back to installing the original spring.

Thanks in advance,

Bart
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Joined: August 20th, 2006, 5:36 am

August 10th, 2007, 1:42 pm #2

Hey, Bart, I did a gas ram install on a .177 CFX almost a year ago, it's still going strong. Used the tape per Theoben's instructions, it does compress after awhile, but it still seems to function fine. It's only purpose is to keep the ram centered in the piston. It occurred to me recently that a couple of o-rings would probably work just as well, assuming you could find something that would fit right. I think your idea of the stainless rings is over kill, plus it would increase the piston weight. Not sure what effect that would have.

For reasons that I won't go into here, I got my ram with instructions for a Patriot. Had to do a little trial and error before I got it working. What ended up working for me was completely removing the rear spring seat, no mod needed. The big washer on the end of the ram rod sits right against the breech plug with just enough preload to still need a compressor to install it. I've never seen the proper instructions, so I don't know if that's the correct installation or not, but like I said, that gun's still working great. My brother has it now, but we chronied it just a few weeks ago, it's averaging 890 fps with Superdomes. That's really close to what it was right after the install. HTH, and if you have any other questions, feel free to email me direct. Later.

Dave

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Joined: October 7th, 2005, 4:39 am

August 31st, 2007, 5:56 am #3

Apparently, the Theoben GasRam is not a straight fit for the CFX piston. I saw several pictures on the internet where people used tape to fit the gas strut into the piston.

This surprised me a bit. The piston is not moving relative to the gas strut. But it gets slammed each time a shot is fired. And due to the way the firing mechanism locks, each time the CFX is cocked the piston is bent a little bit (I did not open the CFX yet, so this is by reading on the Internet.

So I would guess after a while the tape will become compressed and allow play between the gas strut and the piston.

So how good is this tape trick?

I have access to a workshop who works up to the micron. And I was planning to make two rings instead of the tape. I was planning to make them in stainless steel, and a very tight fit. One would be screwed to the piston, the other would be kept in place by the front of the gar strut.

Is this a good idea? Or am I looking for too much trouble, and should I go for the tape solution.

Should I use another (lighter) material for the rings?

Instead of modifying the rear spring seat so it fits the gas strut, I'm going to make a new one, so I can still go back to installing the original spring.

Thanks in advance,

Bart
My gas ram has just been installed - I'm a little weary of the tape, but Dave's mod seems to be holding up well.

I wasn't worried about the rear spring guide - you can always get a new OEM one, or do a spring tune and get a kit from Rich from Mich.

My gas ram rocks as far as smoothness goes - still doing some accuracy testing, but so far highly consistent with 5-10fps shot to shot consistency.

Daniel
Way down in New Zealand
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Joined: August 10th, 2007, 5:55 am

September 3rd, 2007, 6:16 am #4

Hey, Bart, I did a gas ram install on a .177 CFX almost a year ago, it's still going strong. Used the tape per Theoben's instructions, it does compress after awhile, but it still seems to function fine. It's only purpose is to keep the ram centered in the piston. It occurred to me recently that a couple of o-rings would probably work just as well, assuming you could find something that would fit right. I think your idea of the stainless rings is over kill, plus it would increase the piston weight. Not sure what effect that would have.

For reasons that I won't go into here, I got my ram with instructions for a Patriot. Had to do a little trial and error before I got it working. What ended up working for me was completely removing the rear spring seat, no mod needed. The big washer on the end of the ram rod sits right against the breech plug with just enough preload to still need a compressor to install it. I've never seen the proper instructions, so I don't know if that's the correct installation or not, but like I said, that gun's still working great. My brother has it now, but we chronied it just a few weeks ago, it's averaging 890 fps with Superdomes. That's really close to what it was right after the install. HTH, and if you have any other questions, feel free to email me direct. Later.

Dave
My CFX is open for the moment.

Measured everything up yesterday evening. I know about the aftermarket parts. But I'm able to let somebody make the parts for almost free. SO it is just a fun project.

The only problem I had was removing the trigger housing. I could get it loose, but it refused to come off. So I started to disassemble the trigger housing in place. Suddenly it came off, so I don't know why it jammed.

I discovered the spring was already bent (with aprox 500 pellets through the barrel).

somebody has an idea why there is so much play in the front spring guide? I would guess it should not cost to much to make a better fit in the first place.
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Joined: August 15th, 2007, 2:26 am

September 6th, 2007, 3:24 pm #5

245 bucks for the kit and another 25 if you want them to install plus $$$ of shipping the gun to them. I can replace a whole lot of springs for that price and add many other mods and still be wayyyyyy under that.I think i`ll keep mine the way it is.Sounds neat but expensive. even if you do it yourself.

JEFFRO67
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Joined: August 10th, 2007, 5:55 am

September 6th, 2007, 4:29 pm #6

My CFX is open for the moment.

Measured everything up yesterday evening. I know about the aftermarket parts. But I'm able to let somebody make the parts for almost free. SO it is just a fun project.

The only problem I had was removing the trigger housing. I could get it loose, but it refused to come off. So I started to disassemble the trigger housing in place. Suddenly it came off, so I don't know why it jammed.

I discovered the spring was already bent (with aprox 500 pellets through the barrel).

somebody has an idea why there is so much play in the front spring guide? I would guess it should not cost to much to make a better fit in the first place.
The price in Europe is cheaper, it would come around 150$

Still not cheap, but it will be good for my ego...



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Joined: August 14th, 2004, 9:24 pm

September 7th, 2007, 6:07 pm #7

245 bucks for the kit and another 25 if you want them to install plus $$$ of shipping the gun to them. I can replace a whole lot of springs for that price and add many other mods and still be wayyyyyy under that.I think i`ll keep mine the way it is.Sounds neat but expensive. even if you do it yourself.

JEFFRO67
I just checked the web page. Does'nt sound like a bad deal once the spring wears out.

Pennsylvania Pistolero
http://airgunartisans.com

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Joined: August 15th, 2007, 2:26 am

September 8th, 2007, 11:27 am #8

Your about $100 bucks short from what they quoted me in an e-mail. on 9-6-07. said they were out of stock anyway.

JEFFRO67
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