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Thread: Operation TX

  1. #16
    shauny is offline Has a taste for the French fancys
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    Quote Originally Posted by T 20 View Post
    Seeing as I'm hosting the AirArms Owners Club charity meeting next month I thought it would be a good idea if I bought an AirArms gun to use over the weekend.

    So I bought a cheap MK2 TX200 in .22" flavour off our very own Edbear for the princely sum of £125, so giving me something to tune and play with.

    Now here's the twist, rather than me just lathing loads of new parts up I've decided to see what could be acheived using easily available off the shelf parts at minimum cost --- This should allow anyone who can strip a TX to replicate what I'm up to.

    Now even though the MK 2 TX has a relatively short stroke I thought I'd shorten it a little bit more and I'm told that the HW77 piston seal is more efficient than the AirArms seal --- so I bought a piston allowing for both. :-


    [url]http://s1138.photobucket.com/user/mickfurniss/media/image.jpg2_zpsm2qhj0gd.jpg.html?sort=3&o=4[/ur
    Now the LGV seal has a central tit that would restrict flow on a TX with it's central port so I dug a 25mm Weihrauch seal out the spares box. :-


    http://s1138.photobucket.com/user/mi...tml?sort=3&o=6


    And this picture shows the difference in piston lengths (LGV on right) :-


    http://s1138.photobucket.com/user/mi...tml?sort=3&o=5


    The difference in piston lengths with the Weihrauch seal fitted measured at 7.8mm, so with the original TX MK2 stroke being 84mm, fitting the LGV piston should drop the stroke down to 76.2mm.


    Well I had a little bit of time this afternoon so I threw my TX together (bone dry) and ran a quick chrono string to see where I was going.

    Results :-

    Hobbies 645 ft/s = 10.99 ftlbs

    Superdomes 604 ft/s = 11.75 ftlbs

    Jumbos 550 ft/s = 10.75 ftlbs


    The above results are just from changing the piston and removing 4mm of preload from the spring.

    If I get a little bit of time in the week I have a few other little tweaks I'd like to try involving shedding a little weight from the piston by way of removing the 6 gram steel top hat and turning the spring round as I have three collapsed coils on the front of the spring which I calculate to add 11 grams to the overall piston weight.


    So there you are this is my starting point and I'll play around to lower the power a bit more and to see if I can make the gun sweeter, though in all honesty it feels really nice how it's running now.




    All the best Mick
    hello mate,where did you get your lgv service kit ? thanks.. shaun.

  2. #17
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    Quote Originally Posted by shauny View Post
    hello mate,where did you get your lgv service kit ? thanks.. shaun.

    I was given it Shaun.

    Originally I was going to build up the front of the TX piston with weld then machine it to take a 25mm Weihrauch seal which would have reduced the stroke by about 4mm.

    Being given the LGV service kit allowed me to have a play without any lathe work which would be of more relevance to most TX owners.

    I understand the kits are available through Armex but would need shipping to your local RFD due to the VCR act.

    The price I quoted of £24 plus shipping is direct to your door from a German supplier.



    My next door neighbour had a couple of shots with my TX earlier to see what he thought of the firing cycle --- when I asked him what he thought he replied, " I give up, how have you made this one recoiless."

    I was going to have another play with the piston weight tonight but unfortunately I ended up working late but I will have another play this week.



    All the best Mick

  3. #18
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    Quote Originally Posted by NickG View Post
    Very close to convincing the wife that I need to be there, Just got to check the diary, fingers crossed

    Just tell her you need to come back here to fetch your lucky shooting cushion Nick.

    With the amount of items you keep forgetting to take home with you I've had to create a NickG lost and found corner in my workshop.




    All the best Mick

  4. #19
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    Quote Originally Posted by T 20 View Post
    Just tell her you need to come back here to fetch your lucky shooting cushion Nick.

    With the amount of items you keep forgetting to take home with you I've had to create a NickG lost and found corner in my workshop.




    All the best Mick
    I know what you mean, old age creeping up, the wife bought me that cushion so probably onto a winner 99%going to be there, just got to sort out my new gun, Have acquired a MK1 TX, action, all newly blacked and ready to build, just got to decide what to put inside it

  5. #20
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    Quote Originally Posted by T 20 View Post
    I was given it Shaun.

    Originally I was going to build up the front of the TX piston with weld then machine it to take a 25mm Weihrauch seal which would have reduced the stroke by about 4mm.

    Being given the LGV service kit allowed me to have a play without any lathe work which would be of more relevance to most TX owners.

    I understand the kits are available through Armex but would need shipping to your local RFD due to the VCR act.

    The price I quoted of £24 plus shipping is direct to your door from a German supplier.



    My next door neighbour had a couple of shots with my TX earlier to see what he thought of the firing cycle --- when I asked him what he thought he replied, " I give up, how have you made this one recoiless."

    I was going to have another play with the piston weight tonight but unfortunately I ended up working late but I will have another play this week.



    All the best Mick
    The.22's are very soft aren't they, I put my shortest stroke lightest piston in Maz's .22 and it barely moves , he is bringing it t0 the AA bash. Be nice to shoot them side by side,
    I have been simplifying things on the piston front, by modding a standard piston for light weight, and o ring by glueing an ally o ring head on the front, that's the same size as the seal, and using a long latch rod to keep plenty of spring room.

  6. #21
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    LGV seals

    I used an LGV seal in my .22 TX 200 with the piston skirt removed. I just machined the 'tit' of flush and re-tested. It produced the same fps/power as it did with the tit on.

    Is the LGU seal the same as the LGV, but without the tit.?

  7. #22
    Snooper601 is offline I likes to polish my trophy
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    No, it has a negative tit in the centre that's bigger than the port.

    Cheers

    John
    Snooper601 Suspect a simple fault, or a simple engineer He who dies with the most toys wins!
    QHAC Official lubricant development engineer.

  8. #23
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    Quote Originally Posted by T 20 View Post
    ... the only advantage with the 77/97...
    heretic!

    Quote Originally Posted by T 20 View Post
    ...With the amount of items you keep forgetting to take home with you...

    All the best Mick
    Warning:I've seen this method used before. Forgetfulness or a surreptitious technique to move in?

  9. #24
    shauny is offline Has a taste for the French fancys
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    Quote Originally Posted by T 20 View Post
    I was given it Shaun.

    Originally I was going to build up the front of the TX piston with weld then machine it to take a 25mm Weihrauch seal which would have reduced the stroke by about 4mm.

    Being given the LGV service kit allowed me to have a play without any lathe work which would be of more relevance to most TX owners.

    I understand the kits are available through Armex but would need shipping to your local RFD due to the VCR act.

    The price I quoted of £24 plus shipping is direct to your door from a German supplier.



    My next door neighbour had a couple of shots with my TX earlier to see what he thought of the firing cycle --- when I asked him what he thought he replied, " I give up, how have you made this one recoiless."

    I was going to have another play with the piston weight tonight but unfortunately I ended up working late but I will have another play this week.



    All the best Mick
    ok, thankyou mick. shaun

  10. #25
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    Quote Originally Posted by 18 Wheeler View Post
    heretic!


    Warning:I've seen this method used before. Forgetfulness or a surreptitious technique to move in?
    I think your 3 piece shooting stool is still there!

  11. #26
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    Quote Originally Posted by shauny View Post
    ok, thankyou mick. shaun
    No problem Shaun



    Quote Originally Posted by T 20 View Post
    I was going to have another play with the piston weight tonight but unfortunately I ended up working late but I will have another play this week.
    Well I couldn't leave it alone so I had another little play today by shedding a little bit of weight from the piston.

    Now when I got the TX from Ed :-

    The piston weighed 237grams
    The top hat weighed 11grams
    The 2 collapsed spring coils added 7.4grams to the piston weight.

    So the all up piston weight of the TX piston was 255.4grams.


    Now the LGV piston weighs in at 252grams so as first tested with the LGV piston the overall piston weight was as follows :-

    The piston weighed 252grams
    The top hat weighed 11grams
    The 2 collapsed spring coils added 7.4grams to the piston weight

    So the overall piston weight was 270.4grams


    Today I turned the spring round putting the collapsed coils to the rear and substituted a Nylon top hat for the steel one giving the following :-

    Piston weight 252grams
    Nylon top hat 2grams

    So as of today I have an all up piston weight of 254grams.

    After a chrono session the velocities are about the same as before losing 16grams in piston weight but the recoil feels to be just a little less than before.

    I doubt I'm going to mess with the gun anymore unless my planed plinking session shows up any problems --- it's running nice enough for me.



    All the best Mick

  12. #27
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    Quote Originally Posted by 18 Wheeler View Post
    heretic!


    Warning:I've seen this method used before. Forgetfulness or a surreptitious technique to move in?
    Absolutely.

    On both counts!!
    THE BOINGER BASH AT QUIGLEY HOLLOW. MAKING GREAT MEMORIES SINCE 15th JUNE, 2013.
    NEXT EVENT :- May 4/5, 2024.........BOING!!

  13. #28
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    The gun's sounding lovely, Mick.
    THE BOINGER BASH AT QUIGLEY HOLLOW. MAKING GREAT MEMORIES SINCE 15th JUNE, 2013.
    NEXT EVENT :- May 4/5, 2024.........BOING!!

  14. #29
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    Quote Originally Posted by TonyL View Post
    The gun's sounding lovely, Mick.
    I had another little play with it yesterday Tone just to make sure I hadn't missed a trick.

    First up I sleeved the transfer port down to 2.5mm which absolutely destroyed the power output, so I drilled the sleeve out to 2.9mm which brought the power back up just short of where I started but there was quite a shot to shot variation in velocity.

    I tore the action down again and added the 4mm preload washer back on the guide, while I was in there I removed the two breach seal O rings and replaced them with a HW77 breach seal with a 0.8mm shim underneath it.

    So now the power is back up and I have a much smaller shot to shot variation --- in all honesty sleeving the transfer port was probably a waste of time but fitting the Weihrauch breach seal was well worth while.



    All the best Mick

  15. #30
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    Taking the port to around 3.4/3.5 would be perfect if it's still full length
    Always looking for any cheap, interesting, knackered "project" guns. Thanks, JB.

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