TX 200 Breech seal

[Phil Russell]

Michael (Vernal) kindly sent me a photo of the 'double' breech seal and I am pretty certain the mystery is solved as it looks identical to the seal for an Hw77/97. I have held an HW seal up against 2 x BS108 seals and they are remarkably similar and I can believe they occupy the same space.
So... out of interest, has anyone fitted an HW seal in a TX or even used 2 x BS108 rings in an HW77? Maybe the HW would need a shim?

And, if you are going to remove the end plug... 27mm is the size. The end is not very deep so make sure the spanner / socket fits well. I needed to heat the end with a gas torch to soften the sealant ... not very hot but hotter than can be hand held. I heated for maybe 10 or 15 seconds playing the heat around the edge of the plug and it undid easily. When I did it, the fitted O ring came out unscathed by the heat.

Cheers, Phil

[Vernal]

Michael (Vernal) kindly sent me a photo of the 'double' breech seal and I am pretty certain the mystery is solved as it looks identical to the seal for an Hw77/97. I have held an HW seal up against 2 x BS108 seals and they are remarkably similar and I can believe they occupy the same space.
So... out of interest, has anyone fitted an HW seal in a TX or even used 2 x BS108 rings in an HW77? Maybe the HW would need a shim?

And, if you are going to remove the end plug... 27mm is the size. The end is not very deep so make sure the spanner / socket fits well. I needed to heat the end with a gas torch to soften the sealant ... not very hot but hotter than can be hand held. I heated for maybe 10 or 15 seconds playing the heat around the edge of the plug and it undid easily. When I did it, the fitted O ring came out unscathed by the heat.

Cheers, Phil

Thanks Phil, in answer

1, After over 80 years of persistent misuse, my memory sometimes takes a while to respond accurately, and on reflection it is just possible that I bought the seals at a not too distant gunshop, and maybe someone sold me those knowing they would fit a TX - apologies to Chambers if that is the case. You may well have solved that mystery.

2, I have just removed the end plug, which was very tight and I had used gentle heat (after removing my nice new breech seal) before seeing your post. There was no O ring at all, but the thread had been sealed with Loctite or something similar, (hence the need for heat) in very poor condition, so I could be hot on the trail of the missing power now. Many thanks.

Plenty of time to get a new O ring (why does t5he O ring box never have the size you need?) before the stock is useable again- or maybe PTFE tape will suffice.

[Phil Russell]

E mail sent re compression O ring.
Well done.
Cheers, Phil

[T 20]

Michael (Vernal) kindly sent me a photo of the 'double' breech seal and I am pretty certain the mystery is solved as it looks identical to the seal for an Hw77/97. I have held an HW seal up against 2 x BS108 seals and they are remarkably similar and I can believe they occupy the same space.
So... out of interest, has anyone fitted an HW seal in a TX or even used 2 x BS108 rings in an HW77? Maybe the HW would need a shim?

Cheers, Phil

Yes Phil.

My .22" MK2 TX running a Walther LGV piston fitted with a 25mm HW 77 seal, is also fitted with a HW77 breech seal.

From memory I put a 0.6mm copper shim underneath the HW77 seal to make up the difference in length.





All the best Mick

[Phil Russell]

Thanks Mick ... excellent information.
But this reminded me of thoughts I have often had. This is one of those instances where it is possible to swap and change one manufacturer's parts, breech seals, piston seals etc for those of another manufacturer. Mainsprings are an obvious case in point and no one bats an eyelid in thinking about it or trying it. But other parts e.g. breech seals seem to attract scant attention. I try to keep notes on information I find on here but it would be wonderful if people posted their experiences of parts compatibility.
Just a thought, and not wishing to hijack this very interesting topic. Maybe a 'sticky' for the experiences. But maybe it would not get much use ....

Cheers, Phil

[FPoole]

Thanks Mick ... excellent information.
But this reminded me of thoughts I have often had. This is one of those instances where it is possible to swap and change one manufacturer's parts, breech seals, piston seals etc for those of another manufacturer. Mainsprings are an obvious case in point and no one bats an eyelid in thinking about it or trying it. But other parts e.g. breech seals seem to attract scant attention. I try to keep notes on information I find on here but it would be wonderful if people posted their experiences of parts compatibility.
Just a thought, and not wishing to hijack this very interesting topic. Maybe a 'sticky' for the experiences. But maybe it would not get much use ....

Cheers, Phil

I can say that the Walther LGU piston will fit a TX200. Mine was lightened to 195 g, but it just never made power and it didn't feel as good as the original Mark1/2 type factory set up. Just another in the list of things so easy to do to a TX200 only to be put back to pretty much factory spec.

[Vernal]

Not really on topic, but as there are some very knowledgeable people following this thread, I wonder if someone could tell me the standard transfer port diameter for a TX? I have checked mine at 3.6 mm, and wonder if this is as original

[Shed tuner]

Not really on topic, but as there are some very knowledgeable people following this thread, I wonder if someone could tell me the standard transfer port diameter for a TX? I have checked mine at 3.6 mm, and wonder if this is as original

3.7mm std, so sounds like yours is normal. If anything it's on the large side - 3.2-3.4 is better

[Phil Russell]

3.7mm std, so sounds like yours is normal. If anything it's on the large side - 3.2-3.4 is better

Once again, excellent info for the 'very useful to know file'.
I had begun to search for TP info and found reference to the TX200 MK3 having a port of around 3.7 - 3.8 with the MK1 and 2 having the narrower port of 3.2.
Can this be confirmed?

Also ... maybe a little off-beat but I was looking at a MK2 compression tube from my spares box that had no BS108 rings fitted and I am sure there is a steel washer or something that would seat under the breech rings. Not sure this is odd or not. Pretty sure I can revolve it using a needle. Or maybe my eyes are playing up. Any ideas?

Cheers, Phil

[Phil Russell]

I can say that the Walther LGU piston will fit a TX200. Mine was lightened to 195 g, but it just never made power and it didn't feel as good as the original Mark1/2 type factory set up. Just another in the list of things so easy to do to a TX200 only to be put back to pretty much factory spec.

Excellent, thank you.
Now in the deep recesses of my mind (and there a lot of holes) I seem to remember something about swapping pistons around but that it was necessary to alter the shape of the 'latch' on the latch rod a tad. Was that the LGU: TX swap?

[T 20]

I can say that the Walther LGU piston will fit a TX200. Mine was lightened to 195 g, but it just never made power and it didn't feel as good as the original Mark1/2 type factory set up. Just another in the list of things so easy to do to a TX200 only to be put back to pretty much factory spec.

I never lightened the LGV piston I fitted in my .22" TX, I just fitted a HW seal and that was about all I had to do to get an easy 12ftlbs from the shorter stroke.
I fitted the HW breech seal because after fitting the piston the velocity was a little bit inconsistent --- after fitting the new breech seal all was good.

http://www.airgunbbs.com/showthread....7-Operation-TX




All the best Mick

[TonyL]

Thanks Mick ... excellent information.
But this reminded me of thoughts I have often had. This is one of those instances where it is possible to swap and change one manufacturer's parts, breech seals, piston seals etc for those of another manufacturer. Mainsprings are an obvious case in point and no one bats an eyelid in thinking about it or trying it. But other parts e.g. breech seals seem to attract scant attention. I try to keep notes on information I find on here but it would be wonderful if people posted their experiences of parts compatibility.
Just a thought, and not wishing to hijack this very interesting topic. Maybe a 'sticky' for the experiences. But maybe it would not get much use ....

Cheers, Phil

I think that would be most useful, Mr R.

[TonyL]

Michael (Vernal) kindly sent me a photo of the 'double' breech seal and I am pretty certain the mystery is solved as it looks identical to the seal for an Hw77/97. I have held an HW seal up against 2 x BS108 seals and they are remarkably similar and I can believe they occupy the same space.
So... out of interest, has anyone fitted an HW seal in a TX or even used 2 x BS108 rings in an HW77? Maybe the HW would need a shim?

Cheers, Phil

Yes Phil.

My .22" MK2 TX running a Walther LGV piston fitted with a 25mm HW 77 seal, is also fitted with a HW77 breech seal.

From memory I put a 0.6mm copper shim underneath the HW77 seal to make up the difference in length.

All the best Mick

Brilliant, priceless information, people. Thank you for sharing. Yet another shining example of the power of the BBS. I've not had to change the seal(s) on my TX yet, but would prefer the more substantial seeming (to me) HW seal + shim. I wonder if some of the aftermarket suppliers pick up on this and produce a direct replacement HW style one?

[evert]

Brilliant, priceless information, people. Thank you for sharing. Yet another shining example of the power of the BBS. I've not had to change the seal(s) on my TX yet, but would prefer the more substantial seeming (to me) HW seal + shim. I wonder if some of the aftermarket suppliers pick up on this and produce a direct replacement HW style one?

I know at least one maker of aftermarket HW breech seals makes them longer than factory spec. That way they can be fit to guns requiring different seal lengths.

[TonyL]

Excellent information, evert.

Taking a wild guess at a Custom Air Seals offering?