Air Arms Breech O-rings

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DoggBoy said:
if I can get the gun working properly I'll try to find a single shot tray for it and quit dicking around with re-indexing the existing mag. Single shot works fine in my use case but I haven't found one for 25 cal yet.
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I can print you a single shot adapter if you decide to use one. I use them on my FX crowns and my panthera.
 
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So I have the gun back together. Other than a few not so tight screws, everything looked to be in good shape. No blemishes on the probe or the breech. The cocking lever wasn't loose on the end of probe so no issue there.
Now I have to repressurize the cylinder.
With a hand pump.
I'll get back to you in a week or so:censored:
At this point I am leaning towards improper sized O-rings as being the problem. I guess I'll find out in a while.
I assume all manufacturers will use different cross sections and outer diameters to fit their particular groove sizing, but for a 25 cal O-ring would the inner diameter be the same? The pellets I have, H&N Hunter Extreme are 6.35mm at the business end but closer to 6.45mm at the skirt.
I'm sorry I'm so clueless about this. Even though I've had the gun for 6 years or so, it's my first pcp.
 
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@DoggBoy what size orings are you using? From what I can find this is the correct size: cross section - 1.5 mm ID - 6.35 mm 70 NBR. The ID is a guess but the .22 and .177 show the ID being the same as the pellets OD for .177 @ 4.5mm and .22 @ 5.5mm. The oring size chart for the S510 only listed the size for the .177 and .22. Pyramid air has a 2 pack of seals for the .25 in stock for $10.
 
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LDP said:
@DoggBoy what size orings are you using? From what I can find this is the correct size: cross section - 1.5 mm ID - 6.35 mm 70 NBR. The ID is a guess but the .22 and .177 show the ID being the same as the pellets OD for .177 @ 4.5mm and .22 @ 5.5mm. The oring size chart for the S510 only listed the size for the .177 and .22. Pyramid air has a 2 pack of seals for the .25 in stock for $10.
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The envelope they came in says 1.5 by 6.
I'm guessing this is a "There's your problem lady" moment for me.
 
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DoggBoy said:
The envelope they came in says 1.5 by 6.
I'm guessing this is a "There's your problem lady" moment for me.
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I cant say for sure but I bet the 6mm ID is just a little small and the orings getting pushed out of the groove from the pellet then gets wrecked from the pulse of high pressure air. I found 1.5mm x 6.5mm orings @ orings and more. I bet they would work better or you can get the official ones at pyramid air they just cost a little more than the orings and more ones.
 
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LDP said:
I cant say for sure but I bet the 6mm ID is just a little small and the orings getting pushed out of the groove from the pellet then gets wrecked from the pulse of high pressure air. I found 1.5mm x 6.5mm orings @ orings and more. I bet they would work better or you can get the official ones at pyramid air they just cost a little more than the orings and more ones.
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I'll order the proper ones and a full oring kit once my credit card is replaced. Had to cancel it due to the Ticketmaster hack. PITA.
Thanks
 
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This place has 1.6 x 6.35, an unusual size that may or may not work. You can call them and ask, they are on the forum occasionally.
IMG_3192.png
 
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Received my o-rings from Pyramid this morning. Measuring the breech rings it seems they are indeed 1.5mm cross section by 6mm ID.
This is a size I have tried before and still had the problem.
When measuring the pellet probe however it is 5.55 mm. The probe is supposed to form a seal with the o-ring, correct?
I had a crazy thought. Given that I have had this breech seal problem from the beginning would it be possible I have a probe for a .22 rather than a .25?
Anyone have either a Air arms .22 or a .25 and be able to take a quick measurement with a caliper?
I can't figure how a 5.55mm probe could seal in a 6mm o-ring but the list of things I do not know is extensive, to say the least.
I have contacted AA as well.
 
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DoggBoy said:
8.
Years.
I feel like a dolt but if you don't know it's wrong...........
Maybe instead of thinking I'm an idiot, I'll tell myself I'm stubborn.
Or determined.
Sigh.
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I hear ya. You'd never think a company like AA would make a mistake like that, but it does happen. Humans are funny like that.

Now the issue is getting the correct bolt. Could possibly have it sleeved with brass tube or something. Maybe one of the members here who make custom parts can help you? Or maybe someone has a 25 cal bolt laying around?

Really sucks man.
 
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Dr. Kralenstein said:
I hear ya. You'd never think a company like AA would make a mistake like that, but it does happen. Humans are funny like that.

Now the issue is getting the correct bolt. Could possibly have it sleeved with brass tube or something. Maybe one of the members here who make custom parts can help you? Or maybe someone has a 25 cal bolt laying around?

Really sucks man.
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In a perfect world either AA or the retailer will provide the correct part, assuming that is indeed the problem.
Or they will ask to have the rifle sent back at my expense to have it checked and perhaps refitted.
In the real world I'm assuming I'll potentially end up making a new probe. I have a lathe and some basic machining skills.
I am hoping to be pleasantly surprised but more than ready to be marginally disappointed.
I like the gun, but am also ready to try something different.
Choices are somewhat limited here in Canada.
I should probably concentrate on fixing one problem before potentially buying another.
 
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