Wobble on TX cocking lever

[IanV]

Gents, I hope you're all doing well. Was hoping for some advice. This could be just a quick answer from you. It's just I've never done this before. Lol. My TX's groups have opened up and I suspect it's because the cocking lever is not fully secured by the detent. There was a rubber mushroom looking thing on the barrel before that must have fallen off but just didn't notice. Was this the part that ensured the cocking lever wasn't wobbling? I suspect no, it has to be the detent that secures it. I also looked at where the barrel was joining into the rest of the action since some people say the barrel/barrel shroud (didn't even know the TX had a barrel shroud) can drift due to recoil, and it seems all is good. No indication of parts drifting. Looked at the cocking linkage and there doesn't seem any indication of drift too. Which leaves the detent assembly... I have no idea how the detent could drift back, but ok. The hex screw seems really tight. Guessing it's locktightened on? So I just need to take a heat gun to it, melt the locktight and adjust the detent?

[Frank in Fairfield]

That mushroom thing was to keep the cocking lever from slamming into the barrel when you return it to battery. It was installed at the factory and cannot be replaced by you unless you remove the barrel and sleeve. I have tried. We put an O-ring on the end of the cocking arm to do the same thing. NO, I do not know what size. Measure it and go to the store. Your groups have nothing to do with the little rubber bumper.

[Roadworthy]

Frank is correct.  Your groups have nothing to do with the bumper.  Your problem may have to do with a leak at the breech seal, though.  You can try the tissue test to see if you have leakage there.  I store my TX 200 with the cocking lever in the unlatched mode.  When latched there is constant pressure on the breech seal, compressing it.  Over time it takes a set in the compressed position and does not seal well.  Note, the breech seal consists of two O rings.

[Motorhead]

Yup ... agree with ALL above.

As too breech seal and it having sufficient sealing ... When rifles cocked & cocking handle is locked, IF THE LINK that connects the handle back to the shoe is wiggly "as in" Loose / Rattly you don't have a good seal upon the gun firing.

[IanV]

Thank you everyone!

Wow... I don't know what to say right now. Storing the rifle with the cocking arm loose is news to me. Thomas, what you described is such a terrible design flaw, I don't know how AirArms could sign off on it or why they haven't corrected it over the years. But, it makes perfect sense. The TX is my least used rifle and has been set aside with the cocking arm closed all that time. I'll try the tissue test as well as check MV when I get home later. I'll also ask Tony Leach about this. The internals have been modified to a 22mm skirtless piston set up. He may have replaced the o-ring breach seal with something else.

Again, thank you Frank, Thomas and Scott.

[Brazos]

The 2 o-rings to use in the 2 groove in the cocking arm can be either a #8 or #9.  Either will fit.  I guess #9 is bigger so use that one.  My rifle has one #8 and one #9.  Only reason is I tried a #8, it fit, so the second I used a #9 and it also fir.  I just left it that way.  Yes store the rifle with the cocking arm open (not cocked, just loose). 

[Buldawg76]

If it is a fairly recent 22mm kit then it has a delrin breech seal not o rings and that can be easily checked by partly cocking the lever to be able to look in the breech and examine the front of the compression chamber to see if it has a rubber o ring or plastic looking seal.

If it has a delrin " plastic looking seal" then it is crucial that the lock up between the compression tubes sliding shoe, cocking arm pivot and cocking arm latch all be exact so there is no free play with the ball and arm latched. To properly check this the spring needs to be removed so only the cocking components can be evaluated for proper tension against the delrin breech seal when latched. The cocking arm should encounter some slight resistance with the arm about a 1/4 to 1/8" away from contacting the ball detent and latching closed. It does not take much pressure on the delrin breech seal but does require some to seal properly.

BD

[RawDog R1]

The current TL 22mm kit breach seals consist of delrin transfer ports that use one o-ring.
The 5mm long delrin port has a shoulder that accepts one O-ring that will in turn crush when the cocking arm is closed. Very similar to the stack of 2 O-rings that Air Arms uses on the factory TX breach seal.

[Buldawg76]

Yep just had a biddy install a recent 22mm kit and it has the delrin/o ring setup. I am assuming there was some fitment issues with just the delrin breech seal from one gun to another due to tolerance stack up issues.

I have an original 22mm kit with 2 o ring in my TX and a second gen 22mm kit with just delrin seal in my B-40 and did have to shim them delrin to achieve proper breech lock up to get a good seal. Tony did send me a couple thicker delrin breech seals with a kit I installed for another friend that solved the shimming issue.

Getting the correct tension/lockup on the breech seal be it delrin or o ring is critical for proper shot cycle and operation. there are several areas that need to be inspected for proper fitment.

BD

[larspawn]

Yup and I tend to store my break barrels “broken” so as not to compress breech seal.  I leave my TX “broken” too.

[Buldawg76]

Yup and I tend to store my break barrels “broken” so as not to compress breech seal.  I leave my TX “broken” too.

As do I.

BD

[burjaka]

Frank is correct.  Your groups have nothing to do with the bumper.  Your problem may have to do with a leak at the breech seal, though.  You can try the tissue test to see if you have leakage there.  I store my TX 200 with the cocking lever in the unlatched mode.  When latched there is constant pressure on the breech seal, compressing it.  Over time it takes a set in the compressed position and does not seal well.  Note, the breech seal consists of two O rings.

Nice tip.
Thanks.

[Motorhead]

While an older thread .... FYI on the cocking handle being left unlatched when stored
IMO it does NOTHING simply because the main spring has the piston bottomed out and is pushing the Comp chamber forward against the seal already.
That alone will crush the breech seal and flatten it over time.

JMO on this ...
Scott

[Buldawg76]

While an older thread .... FYI on the cocking handle being left unlatched when stored
IMO it does NOTHING simply because the main spring has the piston bottomed out and is pushing the Comp chamber forward against the seal already.
That alone will crush the breech seal and flatten it over time.

JMO on this ...
Scott

Agree also as to keeping arm latched has no effect on compression of breech seals as compared to mainspring pressure keeping them smashed under its tension. I keep arm unlatched just to keep load off cocking shoe, link and ball detent long term during storage.

My underlevers all are setup to cam over slightly when latched to insure tight breech seal.

BD

[Frank in Fairfield]

All of my springers are unlatched except the Daisys and the 300...
Too late to change now..

[IanV]

Hello again everyone.

Hope you're all doing well.

Just a quick update on the issue. So, I haven't exactly done anything to the TX all this time . It's just when the range was shut down due to covid 19, that pretty much took away the only place I could shoot. Can't even legally shoot in my backyard here (Canada) so I just shelved this issue for later when I can start shooting again. Upon closer inspection today, it seems there's a bit of play where the cocking shoe attaches to the comp tube. I tried the tissue test and the tissue doesn't moved at all so the breech seal should still be good. So it has to be the shoe causing the play on the cocking arm and letting it wobble with each shot ruining the rifle's precision. A bit of google-fu indicates the best fix is to shim the shoe or get an oversized shoe from ARH (unlikely right now). Well, time to get to work...

Again, thanks all!

[limbshaker]

Cock the gun, and close the lever back up. Try and move the compression tube back and forth with your fingers. If it moves, your lockup is off, and the breech seals are likely not sealing. The tissue test won't reveal small problems with the breech seals in my experience. A poor lockup can cause the breech seals to get hammered out in short order.

Maybe the breech seals, or maybe a worn hole in the link, or maybe just the shoe. I'd pop some new breech seals in it before doing anything else. Those cocking shoes were sintered steel at one time and pretty cheesy. I tig welded a bead on the leading edge of the shoe on my last one and filed it down to get the lockup right. Shot great for a while then the hole in the cocking arm wore oblong, and it was back to being iffy again and eating breech seals. 

I've owned two TXs over the years and had the problems you are having on both. Needless to say they got adopted by someone else who loves TXs 

Address the shoe and get it fitted just right and it will probably shoot well for a long time. The arm will wear eventually, but it takes a lot of shooting.