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Thread: Softer HW99 Mainspring?

  1. #16
    Join Date
    Apr 2012
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    Retford, Notts
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    Quote Originally Posted by PhatMan View Post
    Bill,

    I fitted a 0.22" Wonky Donky service kit into my 0.177" HW99S, and it made ca. 10.0 ft.lb, with no compression washers fitted.

    Lovely to shoot, and much easier to cock that when the rifle is at ca. 11 ft.lb.

    Russ
    Very nice to know, Russ.

    Thank you.
    THE BOINGER BASH AT QUIGLEY HOLLOW. MAKING GREAT MEMORIES SINCE 15th JUNE, 2013.
    NEXT EVENT :- October 27/28, 2018. BOING!!

  2. #17
    Join Date
    Mar 2006
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    21,764
    Quote Originally Posted by maximus View Post
    TX mk3 springs are quite weedy so may be worth a look to see if they would fit.
    I have no idea of what preload the full TX200 Mk.3 spring would give but, with just 71mm of stroke, it would make so little energy available to the piston that muzzle energy will be low, somewhere in the region of (in round figures) 6 ft. lb. from 25mm preload, 7 ft. lb. from 30mm p/l. and 8 ft. lb. from 40mm p/l, quite possibly less.

  3. #18
    Join Date
    Nov 2008
    Location
    Preston
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    1,823
    Quote Originally Posted by BTDT View Post
    I have no idea of what preload the full TX200 Mk.3 spring would give but, with just 71mm of stroke, it would make so little energy available to the piston that muzzle energy will be low, somewhere in the region of (in round figures) 6 ft. lb. from 25mm preload, 7 ft. lb. from 30mm p/l. and 8 ft. lb. from 40mm p/l, quite possibly less.
    Oh well, give that one a miss then!! I recently fitted guides and top hat to a 99 in 177 using the std spring and it did just over 11. The pre-load was slightly increased due to the addition of the top hat and slip washer. As you would expect it was snappier than my own 22 version but I preferred it to my 177 95 which will be short stroked by 10mm at some point.
    Plinkerer and Tinkerer

  4. #19
    Join Date
    Mar 2006
    Location
    Worcester
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    A softer spring would either need to have a wider coil diameter (probably not feasible due to piston internal diameter), have thinner than standard 3.1mm wire (would struggle to deliver enough energy to the piston without massive preload due to the 71mm stroke) or have more coils (with the same free length).

    If anyone can persuade Jon to measure the spring in his HW99, perhaps we could find out what rifle it was made for.

  5. #20
    Join Date
    Apr 2002
    Location
    Near Wimbledon, SW London
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    20,291
    Quote Originally Posted by BTDT View Post
    A softer spring would either need to have a wider coil diameter (probably not feasible due to piston internal diameter), have thinner than standard 3.1mm wire (would struggle to deliver enough energy to the piston without massive preload due to the 71mm stroke) or have more coils (with the same free length).

    If anyone can persuade Jon to measure the spring in his HW99, perhaps we could find out what rifle it was made for.
    another - when I get round to it Mine has more coils, slightly closer spacing, and was about 10mm longer than std...
    I'm currently looking for: an old style Parker Hale (not Pax) Pheonix, a .177 mk1 Meteor barrel ( or a whole gun if cheap), and a project Crosman 2200 (or bits). Thanks, JB.

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