LG Striker Bounce

Discussion in 'Steyr' started by cloverleaf, Mar 25, 2019.

  1. C.Eaton

    C.Eaton Confirmed Anschutz Nut...

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    Maybe then the hammer needs to be physically fixed to the spring which is also anchored, so that the hammer hits cleanly once but then is pulled back and damped by the spring?
     
  2. hmangphilly

    hmangphilly Can't Re Member

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    I keep thinking about a slight variation on this Steve .
    I'll get around to it one day
     
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  3. cloverleaf

    cloverleaf Active Member

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    Thanks for the thoughts chaps :)

    Yup; fine in principal to an extent - the cost incurred being that you'd need a decent-sized weight of comparable mass to the original striker; meaning more striker spring energy required. Plus it'd be extremely sensitive to timing. Again I think the biggest issue in this case would be implementing it in the 6mm OD Steyr striker!

    Unfortunately this system can't really work to arrest bounce since the first strike (that actually fires the pellet) gives the most valve displacement, so would be the most affected by the resistance of the O-ring; with subsequent strikes (the ones you actually want to damp) being less affected.. so it would work in the opposite way to what we want.

    As per my previous post, the "slingshot" system has limited ability to control bounce. Forcing the striker back with even more force would (with air) make the problem even worse, unless it was sufficient to cause it to latch on the sear again (a'la the semi-auto Hunting 5A) but this would be far from ideal in a single-shot design for many reasons. Your suggestion did make me think about the possibility of venting some air into the striker to provide a forward-acting / counter-force to that of the exhaust valve spring / air pressure in the cylinder pushing it back, but I think this would be difficult to implement and would mean losing air; so not a great move considering we're trying to improve air efficiency!

    The hammer already is effectively fixed to the spring, and springs don't damp anything; returning most of the energy that's input to them. I did wonder about a setup where the spring is attached to the striker and over-extends to hit the valve; in the hope that after the first strike the system would no longer have the energy for the striker to hit the valve a second time, although I suspect this idea is flawed in many ways too!

    Nothing's ever easy, is it...?
     
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  4. Total SS

    Total SS Member

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    The biggest issue here is that the hammer at no time is in "free travel" the hammer does not hit the valve in free motion. the spring is pushing the hammer against the valve.
    if you remove the reg and the air chamber you will see that the valve does not sit in a closed position the hammer keeps it open. this is why i think the valve spring is needed to push against the hammer to close the valve. this is also why you hear a noise when you close the bolt if it is not cocked, the hammer is pushing the valve and opening it until the valve spring closes it again.

    this is also why there is tension on the speed adjuster. when you add spring tension you are fighting against the valve spring. if there was no contact with the valve then the adjustment would be a very loos turn as there is no counter force.

    with this current system there is no way to prevent hammer bounce. the entire system would need to be re designed. it works as is but could it be better yes.
     
  5. hmangphilly

    hmangphilly Can't Re Member

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    The hammer is really light Errol ,the latest version is a redeign of the original and is difficult design to get much extra weight up the front .

    The Fac hammer has extra weight at the back end , but that may not be ideal as that energy has to be trnsmitted through the very thin shaft / stem .

    I have seen 2 bent hammers lately .
    1 was straightened and a couple weeks later found to be bent again .
    I keep pondering how to get extra weight in the hammer . I'll get there some time.
     
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  6. Total SS

    Total SS Member

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    the new hammer design comes from the electronic trigger. one hammer for all rifles.
    the only way would be to make a sleeve to fill the cut out piece in the new hammer.
    you could drop the valve spring pressure and then drop the hammer spring pressure, this would drop the force behind the hammer blow.
     
  7. cloverleaf

    cloverleaf Active Member

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    I agree that it would be better if this wasn't the case, however that's not the direct source of the bounce; which would still be present even if running zero / negative spring preload (that still provided enough striker energy to get the desired result).

    The spring is only one force acting to close the exhaust valve - there's also an air pressure differential acting over the length of the valve (which usually accounts for the bulk of the load holding the valve shut), so lessening the return spring won't help a lot. In addition the higher exhaust spring loads help to flatten out the velocity curve / bias the rifle to work at a higher operating pressure; which aids efficiency.
     
  8. hmangphilly

    hmangphilly Can't Re Member

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    We like the strong return spring
    They are going into walthers too at the moment
     
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  9. C.Eaton

    C.Eaton Confirmed Anschutz Nut...

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    I'm sure there must be a way to get the valve more balanced so that the impulse from the hammer strike is minimal to get the job done as it seems that it is the over force required that is causing the bounce surely?
    Probably already tried but how about a light coil spring around the valve stem that is weak enough to allow one good strike, but then keeps the hammer away from the valve for the subsequent bounces?
    I guess some decent slo-mo through a cutaway action would be enlightening.
     
  10. RobF

    RobF Administrator Staff Member

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    The spring performs a number of functions. If the reg chamber is purged for some reason then it closes it so the gun doesn't need to be cocked when it's refilled (like anschutzs and pro-targets can do). It also reduces valve bounce. And as Cloverleaf says... The spring can't be matched because the force of opening is higher when it's closed than when it's open.

    What you need is a high speed high pressure solenoid. I've found one but it's only rated to 8 bar, not 80.
     
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  11. C.Eaton

    C.Eaton Confirmed Anschutz Nut...

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    I know nothing about Daystates, but don't they use a solenoid or is that to just to strike a valve?
     
  12. RobF

    RobF Administrator Staff Member

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    You and me both! I don't know.
     
  13. SteveC200

    SteveC200 Well-Known Member

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    The solenoid hammer is just to strike the valve, which is an entirely conventional firing valve. The only spring, bar the firing valve spring, is a weak return spring to hold the hammer away from the firing valve, hence no bounce or multiple hits on the valve.

    [​IMG]
     
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  14. C.Eaton

    C.Eaton Confirmed Anschutz Nut...

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    Aha, so my theory might work for Steyrs then. Looking at that cutaway (awfully nice of you to slice your action for us) that’s an awful lot of volume in the compression chamber, that must be an FAC or is that standard?
     
  15. hmangphilly

    hmangphilly Can't Re Member

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    we did that in a wather with a daft light hammer ( 16g ) .

    The hammer was shorter than oe so we coupled it with a floating shuttle .
    We got erratic power depending on where abouts in the hammer channel the shuttle was at the time of firing , so we hollowed the shuttle out a bit and installed a light spring to keep it under light pressure to the hammer . It deffo takes some energy away from a rebounding hammer . Hard to adjust though .

    there are a few anti bounce designs most seem towork on overcoming an additional spring for the shot .

    I still like steves idea with a tweak or 2
     
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  16. C.Eaton

    C.Eaton Confirmed Anschutz Nut...

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    So do I. Taking it further I'd be inclined to try something like the attached, where the hammer locates over the striker:

    IMG_0251.jpg
     
  17. RobF

    RobF Administrator Staff Member

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    I'm not sure the hammer bounces off the chassis. I'm fairly certain the hammer is pushed back onto it's spring by the valve closing due to it's return spring and the 80 odd bar. We know by increasing reg pressure you reduce valve bounce and vice versa. Increasing spring force also does that.

    So in the above scenario, when would the hammer hit the o-rings but not the valve?
     
  18. C.Eaton

    C.Eaton Confirmed Anschutz Nut...

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    Just when I should be busy now the juices are flowing.
    Ok scrub above, sussed it.
    Basically think of the mexican jumping bean scenario but inside the hammer.
    The ball bearings moving insdie the hammer during it's cycle basically damp out any movement back to the striker.
    With this design more or less bearings can be added to vary the weight of the hammer as well, plus the moveable plug allows fine-tuning of the rearward impulse:
    IMG_0252.jpg
     
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  19. RobF

    RobF Administrator Staff Member

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    Ok. Devils advocate. How does the mass of 3 small ball bearings dampen the mass? How do you stop them from just rolling and staying in the same place as the hammer moves back and forth? How do you ensure they are in the same place for each hammer release?
     
  20. nemesis

    nemesis 55yrd standing expert, or was it 8 or 9?

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    Id like to see that working with an uphill or downhill stander lol.
     

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