GTA
PCP - HPA - C02 Gate => Crosman Discovery Forum => : AK-one-shot January 05, 2010, 03:20:50 AM
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I have a leak back past the bolt when firing a pellet.
The steel breach and rifle barrel arrived, and I got them installed on the .2240 without any problem (but I do not like the little allen head screw in the chamber) . Everything seemed to align fine, but upon shooting the gun, I have a gas leak from around the bolt.
Accuracy is great on the hallway range, but I know I'm loosing energy that could be driving the pellet.
Anybody have a suggestion?
Gordon
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Could be that your port seal is not properly seated or the probe o ring is cut.
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I have had the breach apart again, and the port seal is not where it is leaking. The probe O-ring looks OK to my bifocal eyes, but I'll have to get some magnification to check it better. Would an O-ring from NAPA suit my needs, or should I get it from Crosman?
Thank you for the suggestion.
Gordon
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I replaced mine last year with buna and I think it's #006 o-ring. Napa should have it and just bring your old one. Yoou can also check the one on your probe to see it's loose or touch it with something blunt and if it move around it needs changing. Don't forget to usea drop pellgun oil or 30wt non-detergent oil every 4 or 500 shots on tip of cart to rejuvenate the seals. If you over tighten it cap you will restrict the cartridge seal and or cut the seal itself.
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Hi again Bentong,
Thank you very much for the o-ring suggestion, and about oiling the probe & o-ring. That is something I had not thought of. Is pel-gun oil a synthetic, non-dieseling oil?
Gordon
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...you can forget dieseling, but can't use just any-old-oil on o-rings. PellGun oil will work just fine, o-rings are what it was made for.
One more thing to check. you just put on a new breech....is the barrel set all the way back into the breech? If the barrel is just a little more forward in the breech, a perfectly good bolt probe o-ring will still leak as it never finds a good seat.
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Hi Robert,
Thank you for the info on the pellGun oil. The barrel is seated all the way back. In case I damaged the o-ring, I have it on my list for my next Crosman order.
This gun will eventually be a PCP, and I'm looking forward to making that change for winter hunting.
Gordon
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(http://www.crosman-air-pistol-owners-forum.com/pics/Brutuz/seal/seal.jpg)
maybe this could solve the problem if you are sure the barrel port hole is alligned to the breech port hole.
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Hi Brutuz,
Does that probe seal fit over the probe, and ride forward to seal as it pushes the pellet into place?
Thank you for the photos and the idea.
Gordon
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The seal is used as probe seal in a .177 QB78, in the picture it is shown as a Crosman 13xx/22xx barrel seal.
From a Crosman point of view it has nothing to do with the probe.
CharlieDaTuna sells these seals (http://../jscripts/tiny_mce/plugins/emotions/images/smiley-smile.gif)
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Hi Robert,
I double checked, and the barrel is seated all the way into the breach. I also picked up the Crosman PelGun oil.
Thank you.
Gordon