Air Arms TX200 Breech Seal problem

[longdog]

This is a picture of my upper breech seal after 5-600 shots since I replaced it for the same reason.
Thought I'd ask here to see if anyone might have a fix. These are supposed to be "factory type" breech seals.
Thanks

 

[Motorhead]

The 2 stacked seals are nothing more than 90 duro metric Buna O-rings. So an easy replacement.

BIGGEST ISSUE that creates troublesome issues with some TX's is when cocking lever is in battery the cocking link from handle to shoe has slack ( As in wiggles around ) If the case, the breech is NOT compressing against the o-ring/s and upon firing the breech is bouncing at the barrel to seal contact area.
Shimming the shoe rearward a tad can help, new shoe etc .. It is an issue & there are remedies

 

[longdog]

Thanks Scott.
My cocking link has zero slack when "locked up". No movement anywhere in the linkage.
It appears that the fit could be too tight? It's some how shaving a very thin sliver of the outside of the o-ring almost 3/4 around the outside.
Is it possibly too tight?
Maybe the barrel portion of the breech has a sharp edge and needs to be chamfered? Going to be hard to do without removing the barrel.
Again, this is the second time that I've replaced the top o-ring for this same problem. Maybe it's not a problem? It seems to be sealing well. No loss of velocity at all.
The gun is about 8 months old.

 

[Motorhead]

In the realm of O-rings & failures .... a radial feather of material is EXTRUSION from the o-ring getting crushed and losing containment around the edge.
Softer the o-ring, worse the issue, Harder o-rings will take more punishment.

But YES, your correct in that this issue is not an isolated occurrence and many have similar issue .. self included

 

[longdog]

In the realm of O-rings & failures .... a radial feather of material is EXTRUSION from the o-ring getting crushed and losing containment around the edge.
Softer the o-ring, worse the issue, Harder o-rings will take more punishment.

But YES, your correct in that this issue is not an isolated occurrence and many have similar issue .. self included

Thanks again Scott. I won't worry about it.

 

[drpietrzak]

Mine is similar as well.

 

[longdog]

Where can I find a “harder” o-ring? The o-rings that I have are suppose to be same as OEM.

 

[thumper]

Lockup issues. Been a problem with the TX platform since day one, yet most people seem to act oblivious to it when I have brought it up in the past.

Can be caused not only by the cocking shoe, but tolerance stackup between wear in the pivot points of the cocking lever. I've fixed a couple over the years that were egg shaped. Also the nut in the face of the compression tube can come loose.

The "fix" is to get a properly fitted cocking shoe that's adjusted so that the compression tube headspaces properly against the receiver. Problem is, this is a whole nother can of worms depending on the clearance between the barrel and the face of the transfer port. Cocking shoes used to be available from ARH that were actually machined and not cheap sintered metal, and were oversized to allow for them to be filed down to fit right. I HAVE added a little dab of weld to them before and filed that down with success. But if you get that cheap stock shoe too hot it will be more prone to crack.

Another solution is to simply turn a new Weihrauch style breech seal out of hard urethane. It will last much much longer.

 

[marflow 777]

i was going to post use Urethane Orings but then i thought i would google it
https://www.gatewaytoairguns.org/GTA/index.php?topic=196531.0
now if you thought that 2 urethane Orings might not give enough, you could put a Buna under it to allow compression
but i have no knowledge of the problem but knowledge about Orings
Oring Store has been my go-to place for Oring but there shipping cost have gone up so make a list
https://www.theoringstore.com/store...ct_info&cPath=367_1322_1328&products_id=27564

just some ideas