FTP900 shot cycle time?

Discussion in 'Air Arms' started by Darron, Nov 26, 2015.

  1. Darron

    Darron Reformed Bandit

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    Hi my FTP shoots fantastic groups at 50yds when bench rested, as good as i could expect from any rifle. When i shoot off the bag and as expected the groups open up (whos doesnt hey?). What has become clear is that to perform well with the FTP your technique especially follow through must be perfect (yes i know it should be good whatever rifle you shoot) but the more i get used to my FTP the more it is clear that the cycle or lock time is remarkably slow to other rifles i have used (GC2, Ripley etc). My question is has any body modified there FTP to over come this? shorter hammer stroke, stronger spring? i dont know.

    Thanks
     
  2. Welsh Wizard

    Welsh Wizard My Backs Gone! Staff Member

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    give the gun to another shooter, preferably a higher grade than yourself and let them group with it.
    the ftp I have used could group sub 15mm at 55 y.
    no adjustment needed.
     
  3. Chris58b

    Chris58b Member

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    I'd also be very interested to hear possible answers to this. I shoot benchrest with mine which shows up the smallest flaws easily and have also established that due to slow lock time follow through is even more critical with the FTP.
    Factory settings have the Hammer Spring almost fully wound in and then choked back down to 11.3 ft lbs with the transfer port. Maybe AA have done this in an attempt to overcome the design fault/issue.
    I'm not saying it prevents fantastic accuracy but rather that you need to work harder on follow through to achieve it when compared to another rifle with a faster lock time.
     
    Last edited: Nov 26, 2015
  4. Darron

    Darron Reformed Bandit

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    i agree Chris, will be interesting to see if we get any proper answers to the question rather than the rather predictable give the gun to somebody else response.
     
  5. Darron

    Darron Reformed Bandit

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    I think you might need to read the question again? The FTP i USE groups tighter than 15mm at 55yds when benched indoors. All im saying is i think if the lock time was quicker i could get better groups off the bag as well. Im sure a better shooter will get tighter groups but a grand says that nobody will get a tighter group off the bag with it than i can benched. all im saying is is if the cycle was quicker the gun would undoutably be more easy to be accurate with and i was wondering if anybody had sped there action up.
     
  6. RobF

    RobF Administrator Staff Member

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    Very much doubt it is or you can tell. Lock time of PCP's is typically around 8ms, 8/1000ths of a second. Some are faster (think Daystate got it down to 4-5ms before they tweaked the switch so it didn't go off the same way) and some maybe a ms or so slower.

    Human reaction time is about 400/1000ths, blink of an eye is 50/1000ths. Even the delay you can hear on a stereo system front to back 3yds is in the order of 10/1000th's

    Hammer travel is only going to be a few mm.

    What I think people think is fast or slow is the amount of vibration on the shot.

    You'll never get a gun to make up for snatch or a lot of movement during release. It has to sit there as best as it can and stay there through the shot cycle.
     
  7. TOOL

    TOOL Independent FT Pumper

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    Sprouts are on offer at Aldi
     
  8. Chris58b

    Chris58b Member

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    Logically, you'd think that a stronger spring would be a step in the right direction. However, it is also likely to increase recoil/vibration which may still be minimal but could still negatively affect accuracy. Less of one issue but more of another. Jon Harris has previously commented about the slow lock time of the FTP, especially when compared to the latest Anschutz or Feinwerkbau offerings. I wonder how they are mechanically different to produce faster lock times without increasing recoil?
    In an attempt to squeeze every morsel of possible accuracy out of mine and tame the mechanical recoil/vibration, I removed the AT then wound out the hammer spring and unrestricted the transfer port, balancing them to still give 11.3 ft lb. It now shoots deader than a dead thing but now feel I must really concentrate on follow through to get the added accuracy benefits. This adjustment has all but removed any detectable recoil/vibration but at the cost of lock time. I suppose I just want my cake and eat it.
     
    Last edited: Nov 26, 2015
  9. DYNO DAVE

    DYNO DAVE Senior Member

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    Lock time

    Well it never seesees to amaze me the rubbish that people talk about on here , why would any one want to measure the lock time , just shoot it and enjoy the gun :shot:
     
  10. AIRFIX GILLY

    AIRFIX GILLY WFTA World Champion 2012

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    Ask the 'Murf' youth... He'll know about stuff like this.. He's the Daddy..:eek:
     
  11. Tench

    Tench WHFTA World Champion 2016.

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    The main problem with increasing spring tension to decrease lock time is the added preload the hammer applies to the exhaust valve when the hammer is forward which actually slows the closing of the valve because it has to push the hammer back against the hammer spring and contributes to dumping at low pressure, having to cock before filling etc This has alsorts of undesirable effects like increasing the power difference between different pellet weights, increasing the air used per shot, increasing the jetting at the muzzle. The way to increase spring power without this happening is to shorten the spring.
    A 50mm spring with zero preload compressed by a 20mm hammer stroke will be compressed by 40%, a 40mm spring with the same stroke will be compressed 50%, so more energy can be got from the spring without slowing the valve closing down. Or they could just copy the contained hammer spring setup in the Anschutz which allows the preload on the spring to be set independently of the force applied to the valve.
    The S400 action hammer spring has 23mm of hammer spring preload compression applying force to the exhaust valve when uncocked!! Is it any wonder the HFT500 uses 3x as much air per shot as a BSA gold star.
    My rifles have non and only 1" long hammer springs. This is just another example of manufacturers not developing rifles to be the best they can be. but they do look good so that's allright!
     
  12. TOOL

    TOOL Independent FT Pumper

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  13. RobF

    RobF Administrator Staff Member

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  14. Chris58b

    Chris58b Member

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    I couldn't care less what the actual measured lock time is, what I do care about is the impact it has on my shooting discipline. Longer lock time= more follow through sensitivity= less consistency= Worse score
    This topic doesn't really affect most people as 1 or 2 mm won't make much difference to them but to a benchrest shooter it does.
    Just because you don't care, doesn't mean others don't .
     
  15. Brian.Samson

    Brian.Samson Allowed in Sales Staff Member

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    The OP says he gets brilliant groups bench rested and only has a perceived problem with lock time when he shoots off a bag ( FT sitting style ).

    I assume the lock time is the same between your gun and the OP's, so..... perhaps it's not the gun?
     
  16. simmmo

    simmmo Member

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    I feel supported standings sight pictures after pulling the trigger equate to a miss(with my Daystate Mk3) yet they fall over more often now with my ISPs with a 2mm hammer throw and new lightened hammers. Possibly just a confidence thing but locktime with their Anschutzs trigger and short hammer throw feels quick, flashing through standers has never been so fruitfull.

    Monkey
     
  17. RobF

    RobF Administrator Staff Member

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    To look at it scientifically you need to take into account the lock time.

    If we say it's 10ms. And we say that's giving an error of 2mm.

    there's 100 '10ms' in one second. So we multiply 2mm by 100 and get 200mm, or 20cm in old money. That's moved in one second.

    Now i know people move, but 20cm in one second is quite a lot of movement.

    But lets say that's how bad our hold is, lets make that lock time twice as fast. 5ms. That means we shave 10cm off the movement, the gun still is moving 10cm in that seconds and still moves 1mm.

    If we want to reduce 1 or 2mm down to say 0.1mm or 0.2mm then we need to be making the gun 10x faster. We're in micro seconds here... 500us. Aside from the ridiculously short time that is, it does beg the question if shed engineers (no disrespect meant here) are going to be able to deliver improvements by the factor of 10 over the professional manufacturers. Yep 'we' can improve things... but that well?

    Hold it so it doesn't move 20cm in a second :)
     
  18. Brian.Samson

    Brian.Samson Allowed in Sales Staff Member

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    The only problem with that theory Rob is that the 2mm movement is downrange, not muzzle movement.

    You'd need significantly less movement at the muzzle to see 2mm of movement downrange (can't be bothered to work it out though)

    I've gotta ask the question though - what's the point of trying to modify a gun to completely remove all shooting skill? Improve trigger technique, breathing and follow through.
     
  19. simmmo

    simmmo Member

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    To try and beat you Brian.

    Monkey
     
  20. Chris58b

    Chris58b Member

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    Good point in general,
    If all guns were equal then it would be a real test of ones shooting skill. However, they are not, and people choose their rifle based on many things, accepting that there will be strengths and weaknesses in each model. I'm sure most shooters strive to get the best out of what they have and minimise its weaknesses.
    This is likely why the OP asked the question in the first place.
    That said,
    If I ever actually achieved what I wanted from a rifle, I think I'd get bored pretty quick :).
    A lot of the fun is in the journey itself.
     
    Last edited: Nov 26, 2015

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