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Thread: HW99 Piston Dimensions required ?

  1. #1
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    HW99 Piston Dimensions required ?

    As above, I'm just after the overall length of a HW99 piston --- front of seal to back of the piston rod please.




    All the best Mick

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    Standard original old fashioned soft lipped parachute seal to very back of latch rod is 156mm

  3. #3
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    Quote Originally Posted by brk1 View Post
    Standard original old fashioned soft lipped parachute seal to very back of latch rod is 156mm

    Cheers for that.


    Bugger.

  4. #4
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    Quote Originally Posted by brk1 View Post
    Standard original old fashioned soft lipped parachute seal to very back of latch rod is 156mm
    Ah, just a thought if you have the piston handy --- how far from the rear of the seal to the front of the piston cocking slot ?



    All the best Mick

  5. #5
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    Quote Originally Posted by T 20 View Post
    Ah, just a thought if you have the piston handy --- how far from the rear of the seal to the front of the piston cocking slot ?



    All the best Mick
    What you tinkering with now Mick ?
    B.A.S.C. member

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    Quote Originally Posted by robs5230 View Post
    What you tinkering with now Mick ?
    Long story, Rob.

    I always fancied having a go at tuning an Oldschool HW50 after Jim showed his Venom tuned one in Airgunworld many years ago.

    So I bought a nice HW50 off Mach 1.5 but it was a bit too good for me to mess about with, so I put that one in the gun cabinet.
    Then I bought a HW99 stock off here from Rincewind.
    Then I bought an action from Jonny Neate that he'd bought off the bay, but this turned out to have a buggered barrel.
    Then I bought a HW99 barrel off someone at the Boinger Bash.
    Then I bought another cheap HW50 off Mach 1.5 but decided to stick that one in the cabinet as well.

    So I've now ended up with two HW50s and a big pile of HW50/99 parts to mess about with and put together, but that's a bit too easy so I'm aiming on stroking the poor little thing from 65mm up to 75mm to get her nearer to 12ftlbs for ratting duties.




    All the best Mick

  7. #7
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    Quote Originally Posted by T 20 View Post
    Long story, Rob.

    I always fancied having a go at tuning an Oldschool HW50 after Jim showed his Venom tuned one in Airgunworld many years ago.

    So I bought a nice HW50 off Mach 1.5 but it was a bit too good for me to mess about with, so I put that one in the gun cabinet.
    Then I bought a HW99 stock off here from Rincewind.
    Then I bought an action from Jonny Neate that he'd bought off the bay, but this turned out to have a buggered barrel.
    Then I bought a HW99 barrel off someone at the Boinger Bash.
    Then I bought another cheap HW50 off Mach 1.5 but decided to stick that one in the cabinet as well.

    So I've now ended up with two HW50s and a big pile of HW50/99 parts to mess about with and put together, but that's a bit too easy so I'm aiming on stroking the poor little thing from 65mm up to 75mm to get her nearer to 12ftlbs for ratting duties.




    All the best Mick
    Sure you'll get it sorted
    B.A.S.C. member

  8. #8
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    Sorry Mick, just seen this, rear of piston seal or start of the full diameter of the main piston body to start of the cocking slot is 10mm if I've read you question correctly , If not ask again and I'll remeasure for you

  9. #9
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    Quote Originally Posted by brk1 View Post
    Sorry Mick, just seen this, rear of piston seal or start of the full diameter of the main piston body to start of the cocking slot is 10mm if I've read you question correctly , If not ask again and I'll remeasure for you
    Thank you kind Sir --- that is exactly what I wanted to know.

    That ties in nicely with this picture I found on 'tinternet this afternoon :-

    image.jpg

    Not perfect for my needs but it would be a good starting point so I'll start a wanted ad later.




    All the best Mick

  10. #10
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    Quote Originally Posted by robs5230 View Post
    Sure you'll get it sorted
    The trick is to get it sorted as quickly and as cheaply as possible, Rob.

    Some of the guns I've built owe me over a weeks wages.




    All the best Mick

  11. #11
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    No problems Mick

    Sounds like you had the same but different scenario that I did . I got an old 99s as a lockdown project at the start of lock down (very first one) , I accumulated enough bits and pieces over time trying to build another 99s so I had a .177 and a .22 version, I never managed to complete that gun, I never managed to get the cylinder and the back block/trigger block to be able to complete it, when I got the first gun , there on auction site was a broken for spares 99 , cylinder for sale and the trigger block as well, I didn't want them then, so typical , never seen those parts since , eventually I got very lucky and got a 4 month old complete 99s that was cheaper than the lockdown project was . So now I have both guns.

    I'll still keep my eyes open for those missing bits . I'm still missing the cylinder , the trigger block the trigger pins to hold it to the block and one stock screw , but that depends what model it is , some use 6mm some use 7mm . I like the shot cycle of the .22 , but all my other guns are in .177 , so I still have a choice as to final 99 configurations , either one of each or 2 x .22 or if I ever complete my parts search I'll have the .177 and 2 x .22 as well , I'm in no hurry at all . I actually made myself a stock to fit one 99s and got another one nearly new fron the bay

    Are you trying to build some custom version of the gun?, the HW50 is the European version of the HW99s or so I was led to believe, they easily make 12 FPE , in fact if you have a seal fail that sucks a bit of Moly through they make 23 fpe without even a bang If your building a .22 , they easily make 12 even with a soft Titan No.10 in them

  12. #12
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    Quote Originally Posted by brk1 View Post
    Are you trying to build some custom version of the gun?, the HW50 is the European version of the HW99s or so I was led to believe, they easily make 12 FPE , in fact if you have a seal fail that sucks a bit of Moly through they make 23 fpe without even a bang If your building a .22 , they easily make 12 even with a soft Titan No.10 in them
    Theres always confusion around the HW50...

    The current HW50 is as you say the same gun as the HW99, and both are easily capable of 12fpe.

    The older HW50, which is the one Mick is working on, is a older discontinued model with a 25mm cylinder and a shorter stroke.
    Think of it as a sporter version of the HW55 target rifle.
    Too many airguns!

  13. #13
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    Quote Originally Posted by brk1 View Post
    No problems Mick

    Sounds like you had the same but different scenario that I did . I got an old 99s as a lockdown project at the start of lock down (very first one) , I accumulated enough bits and pieces over time trying to build another 99s so I had a .177 and a .22 version, I never managed to complete that gun, I never managed to get the cylinder and the back block/trigger block to be able to complete it, when I got the first gun , there on auction site was a broken for spares 99 , cylinder for sale and the trigger block as well, I didn't want them then, so typical , never seen those parts since , eventually I got very lucky and got a 4 month old complete 99s that was cheaper than the lockdown project was . So now I have both guns.

    I'll still keep my eyes open for those missing bits . I'm still missing the cylinder , the trigger block the trigger pins to hold it to the block and one stock screw , but that depends what model it is , some use 6mm some use 7mm . I like the shot cycle of the .22 , but all my other guns are in .177 , so I still have a choice as to final 99 configurations , either one of each or 2 x .22 or if I ever complete my parts search I'll have the .177 and 2 x .22 as well , I'm in no hurry at all . I actually made myself a stock to fit one 99s and got another one nearly new fron the bay

    Are you trying to build some custom version of the gun?, the HW50 is the European version of the HW99s or so I was led to believe, they easily make 12 FPE , in fact if you have a seal fail that sucks a bit of Moly through they make 23 fpe without even a bang If your building a .22 , they easily make 12 even with a soft Titan No.10 in them

    It's a bit strange isn't it, there used to be HW99s being broken for parts and sold in sales on a regular basis but I can't recall seeing one for a couple of years now.

    The HW50 I'm trying to sort is pre HW99/50s so is a completely different animal.




    All the best Mick

  14. #14
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    Quote Originally Posted by T 20 View Post
    It's a bit strange isn't it, there used to be HW99s being broken for parts and sold in sales on a regular basis but I can't recall seeing one for a couple of years now.

    All the best Mick
    It's 'coz loads of peeps is finally feeling the lurve for the 99 and keeping 'em, Mick.
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  15. #15
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    I keep toying with the idea of stroking one of my old school HW50 rifles, the deal is you remove 3mm from the back block and change the cocking lever to a modern HW99 one and then .... what? Stick a HW30 piston in it and cut the cocking slot back?

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