GTA
General Discussion To Gateway To Airguns => The Shop => : CaptZippy March 08, 2010, 09:01:39 AM
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Preparing to tune, I noticed something strange with the breech seal. It appears the height of the seal at the bottom is lower than the top. Perhaps you can see the difference in the attached picture. The height of the top of the seal is .019" and the height at the bottom is .006". I think its obvious the seal needs to be replaced, but what troubles me is WHY. It seems that when returning the barrel after cocking, it isn't lining up correctly. Is there a way to adjust the closure gap? Am I worrying about something that is not a problem?
(http://i1000.photobucket.com/albums/af128/CaptZippy/Airguns/IMG_1798-1.jpg) (http://s1000.photobucket.com/albums/af128/CaptZippy/Airguns/?action=view¤t=IMG_1798-1.jpg)
Thanks for your help...
Semper Fi
Tom
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I would think as long as it's not losing compression there it would be ok. Ed
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Hi Tom,
In your picture, the assembly is upside-down, so really the "bottom" of the seal is sticking out a little more than the "top". Probably because the rubber has taken a permanent set. There is more force on the top when the breech is closed because of the increased distance from the pivot pin (think of it as a fulcrum), so it's my guess that this just came from age.
Try the "tissue paper test". If it fails that, replace it or shim it.
Mike
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Ed is right, there probably is nothing wrong with the seal. It is just the way the breech face was cut. You can check it by puting a pellet in the breech and cocking it. Lay piece of tissue over the top where the crack is and shoot. If the paper blows of then you have a leaky seal. Make sure there is no wind..:)
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Tom, for what it's worth my Summit has the same issue. But as Mike stated, mine is flat at the top. I've done the tissue test on mine, as well as a baby powder test and it appears I'm not loosing any air during the shot cycle. So I'd say at least in my case it's nothing to worry about.
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Thanks All!... when I get the new Macari spring and seal and put her back together, I'll do the tissue test as Gene described.
Thanks for your responses....
Semper Fi
Tom