Air Arms Breech O-rings

I have an AirArms S510 .25cal I've owned for 8 years that I am having a difficult time keeping breech seals in.
Sometimes they will last for hundreds of shots and next thing I know I am replacing it every 5 or 6 shots.
I have been getting them from several different suppliers and that seems to make no difference in longevity.
I suspect user error but it is driving me crazy.
I'm tired of having gophers run over my feet while I'm dicking around with the gun.
I have tried several different pellets with no difference.
I'm also tired of paying 25 bucks shipping for 2 or 3 o-rings.
Any suggestions?
 
Tried captain O-ring yet? They carry upgraded breech rings for several guns.

Other than that, I would check the linkage on the side lever and make sure it's not loose or wallowed out. That can cause the probe not to seat all the way into the barrel and will cause blow by which will blast the seal out or shred it quickly.
 
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Tried captain O-ring yet? They carry upgraded breech rings for several guns.

Other than that, I would check the linkage on the side lever and make sure it's not loose or wallowed out. That can cause the probe not to seat all the way into the barrel and will cause blow by which will blast the seal out or shred it quickly.
Thanks for the tip.
The Captain doesn't list Air Arms as a manufacturer they support. Would all 25 cal breech seal orings be the same size?
 
Not necessarily. Could have a different cross sectional width or outer diameter that goes into the barrel groove. I would get a new replacement, measure it, and then order some harder o-rings and try them put. 70 durometer is pretty common, 90 would be harder material.
Good idea, thanks again.
I know there will be a lot of variability here, but how long would you normally expect an O-ring to last?
 
Have you closely inspected the probe? Possible burrs or misalignment? Something there is not right. Even if durometer is too soft you should certainly be getting a lot more shots without trashing the seals.
I have and it seems fine but I'll fully tear down the gun in the next little while and see if I can find the problem.
Thanks.
 
When you cock the gun do you do it with the barrel pointed up at a angle, I read a thread that for some reason the 510 has a problem with eating breech seals if cocked with barrel above horizontal.. The reason I found that thread is I have a .25 S510 that I bought a month or so ago and it ate 3 breech seals in less then 2 weeks and I was cocking gun with barrel pointed up. After I find the thread I started cocking gun level and haven't eating a o ring since.
 
When you cock the gun do you do it with the barrel pointed up at a angle, I read a thread that for some reason the 510 has a problem with eating breech seals if cocked with barrel above horizontal.. The reason I found that thread is I have a .25 S510 that I bought a month or so ago and it ate 3 breech seals in less then 2 weeks and I was cocking gun with barrel pointed up. After I find the thread I started cocking gun level and haven't eating a o ring since.
I think I'm mostly doing it with the barrel pointed down actually. Also the mag advance on my gun is broken so I have to remove the mag, manually advance it, re-insert the mag and then finish cocking the gun. It's when I try to remove the mag after shooting that I realize the O-ring has left the building and blown partially back into the mag. I'm partially through a tear down now and haven't found anything suspicious yet.
 
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When you cock the gun do you do it with the barrel pointed up at a angle, I read a thread that for some reason the 510 has a problem with eating breech seals if cocked with barrel above horizontal.. The reason I found that thread is I have a .25 S510 that I bought a month or so ago and it ate 3 breech seals in less then 2 weeks and I was cocking gun with barrel pointed up. After I find the thread I started cocking gun level and haven't eating a o ring since.
I'm trying to think of a reason that would make a difference. Only thing is that maybe the pellets shift slightly in the magazine and then go in at a different angle, hooking the O-ring on insertion? Maybe?
 
It was said in thread I found that the issue was know to Air Arms and they were supposed to look into it, thread was 2-3 yrs old so not sure if they have or not.. but believe it was due to pellet shifting in mag, so mags were the issue.
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.
 
Not sure why your gun is eating seals - all the usual suspects have been mentioned. I have not experienced that issue in any of my Air Arms guns. S300, 2 x S400's, 4 x S510's and a Galahad. All have just needed seals replaced from normal wear and tear every 5,000 rounds or so (usually much longer than that).

Pyramyd Air has spare .25 breech o rings.

If you are using even very slightly different sized o-rings that would cause them to migrate out of the groove very very often...ask me how I know.

Here is a link to the mag indexing arm. The older ones had issues. This new design is much more robust. Very easy install. Just pop off the mag index plate on the right side of the action, pull the post out and voila. You're golden!