Page 1 of 2 12 LastLast
Results 1 to 15 of 25

Thread: Locktime

  1. #1
    Join Date
    Apr 2018
    Location
    Chirk
    Posts
    2

    Locktime

    Hello can someone explain what locktime is

    And what a short stroke will do ?
    Many thanks Mike

  2. #2
    Join Date
    Jul 2003
    Location
    Leek
    Posts
    383
    Locktime is mainly used for powder burners- time between trigger being pulled and striking the cartridge, can be applied to a PCP as time between trigger and hammer striking the exhaust valve, don't think you can really apply it to a springer as the firing process starts as soon as you pull the trigger where the piston actually has the effect of moving the pellet is anyones guess.

  3. #3
    Join Date
    Oct 2004
    Location
    Nuneaton, Warwickshire
    Posts
    6,781
    Locktime is very relevant to spring powered air guns. It is the time from when the trigger sears have parted, the piston has been driven down the compression cylinder, the pellet starts to be driven down the barrel to when the pellet actually leaves the barrel.


    Neil
    Current airguns:- Steyr LG110: Steyr LP10: Air Arms HFT500: Weihrauch97 fully customised.

  4. #4
    Turnup's Avatar
    Turnup is offline Dialling code‎: ‎01344
    Join Date
    Nov 2012
    Location
    Crowthorne
    Posts
    5,491
    Quote Originally Posted by u.k.neil View Post
    Locktime is very relevant to spring powered air guns. It is the time from when the trigger sears have parted, the piston has been driven down the compression cylinder, the pellet starts to be driven down the barrel to when the pellet actually leaves the barrel.


    Neil
    Although I have no specific source of info, I had always thought the same a ukniel, however some interweb research turns up several different definitions (many of which would seem to be given with only one type of firearm in mind) and I suspect it is one of those terms that means exactly what you want it to.

    FWIW in my opinion, it is only really meaningful if we accept ukniels definition (trigger release to projectile in free flight) since it can then me meaningfully applied to any firearm (even a flintlock or matchlock. crossbow). Can't see why anyone would be interested in how long it takes from trigger release to striking the primer - what use would this info be?
    True freedom includes the freedom to make mistakes or do foolish things and bear the consequences.
    TANSTAAFL

  5. #5
    Join Date
    Sep 2010
    Location
    Exeter
    Posts
    35,658
    Quote Originally Posted by Mike.m View Post
    Hello can someone explain what locktime is

    And what a short stroke will do ?
    Many thanks Mike
    I've always believed it to be the delay between pulling the trigger & the projectile exiting the muzzle.
    With a springer it will cover the double recoil so I'd think it extremely important.

  6. #6
    Join Date
    Jul 2003
    Location
    Leek
    Posts
    383
    Quote Originally Posted by Turnup View Post
    Although I have no specific source of info, I had always thought the same a ukniel, however some interweb research turns up several different definitions (many of which would seem to be given with only one type of firearm in mind) and I suspect it is one of those terms that means exactly what you want it to.

    FWIW in my opinion, it is only really meaningful if we accept ukniels definition (trigger release to projectile in free flight) since it can then me meaningfully applied to any firearm (even a flintlock or matchlock. crossbow). Can't see why anyone would be interested in how long it takes from trigger release to striking the primer - what use would this info be?
    But it doesn't mean you have to relate it to a springer find another term for it. Lock is just that, the firing mechanism, not the time from trigger to projectile leaving the barrel. It's all milliseconds we're talking about but it came about from matchlock to flintlock to cartridge firing times which varied greatly as advances were made

  7. #7
    Join Date
    Jul 2000
    Location
    Tremar
    Posts
    14,239
    If it's the time from the trigger release to the pellet leaving the muzzle then it might be more appropriate to call it an unlock time.
    www.shebbearshooters.co.uk. Ask for Rich and try the coffee

  8. #8
    tinbum's Avatar
    tinbum is online now Killer Vampire Lesbians on scooters
    Join Date
    Aug 2007
    Location
    Daarn Saaarf!
    Posts
    19,386
    As for the second part of your question; a short stroked gun has the piston travelling faster over a shorter distance for the same power. This has an exponential effect on lock time
    God rest ye jelly mental men

  9. #9
    Join Date
    Apr 2012
    Location
    Retford, Notts
    Posts
    34,739
    And for people who are interested, our National Treasure Jim Tyler has, in recent times, covered this very subject in great detail.

    Piston acceleration, piston bounce timings, pellet release, pellet exit, measured recoil and surge, pellet release at certain nodes / anti-nodes etc etc. He has also covered PCPs in these studies.

    All brilliant and fascinating stuff.


    Just that we could do with it all in one handy publication.


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

  10. #10
    Turnup's Avatar
    Turnup is offline Dialling code‎: ‎01344
    Join Date
    Nov 2012
    Location
    Crowthorne
    Posts
    5,491
    Quote Originally Posted by bezzer View Post
    But it doesn't mean you have to relate it to a springer find another term for it. Lock is just that, the firing mechanism, not the time from trigger to projectile leaving the barrel. It's all milliseconds we're talking about but it came about from matchlock to flintlock to cartridge firing times which varied greatly as advances were made
    OK please explain locktime in relation to the function of a matchlock and a flint lock and a percussion lock. The timing starts when and stops when?
    True freedom includes the freedom to make mistakes or do foolish things and bear the consequences.
    TANSTAAFL

  11. #11
    Hsing-ee's Avatar
    Hsing-ee is offline may also be employed in conjunction with a drawn reciprocation dingle arm, to reduce sinusoidal repleneration
    Join Date
    Dec 2001
    Location
    Glasgow
    Posts
    18,217
    Quote Originally Posted by TonyL View Post
    And for people who are interested, our National Treasure Jim Tyler has, in recent times, covered this very subject in great detail.

    Piston acceleration, piston bounce timings, pellet release, pellet exit, measured recoil and surge, pellet release at certain nodes / anti-nodes etc etc. He has also covered PCPs in these studies.

    All brilliant and fascinating stuff.


    Just that we could do with it all in one handy publication.


    PLEASE, JIM!!!!!
    Yeah, what he said.

  12. #12
    Join Date
    Jul 2003
    Location
    Leek
    Posts
    383
    Quote Originally Posted by Turnup View Post
    OK please explain locktime in relation to the function of a matchlock and a flint lock and a percussion lock. The timing starts when and stops when?
    Easy enough, it's the time taken from trigger release to the time the primer/propellant is ignited- matchlock, wheellock, flintlock, percussion and cartridge have progressively had faster and more efficient lock times, all to do with the lock mechanism, nothing at all to do with barrel time then it would be lock-barrel time. If that was the case then it would vary with velocity of every different type of projectile weight/ /load in the same gun, locktime is consistent in a particular gun with whatever ammunition is being used..

  13. #13
    Turnup's Avatar
    Turnup is offline Dialling code‎: ‎01344
    Join Date
    Nov 2012
    Location
    Crowthorne
    Posts
    5,491
    Quote Originally Posted by bezzer View Post
    Easy enough, it's the time taken from trigger release to the time the primer/propellant is ignited- matchlock, wheellock, flintlock, percussion and cartridge have progressively had faster and more efficient lock times, all to do with the lock mechanism, nothing at all to do with barrel time then it would be lock-barrel time. If that was the case then it would vary with velocity of every different type of projectile weight/ /load in the same gun, locktime is consistent in a particular gun with whatever ammunition is being used..
    Matchlock - not all have a trigger so when does the timing start?

    Flintlock and Wheelock - production of sparks?

    Flintlock and Matchlock and Wheelock, ignition of primer or propellant?

    What part of the propellant? (ignitions is progressive)

    How would you measure any of these anyway?

    Cartridge - strike on primer, ignition of part of primer, emergence of primer sparks into propellant, ignition of propellant immediately adjacent to primer, ignition of all of the propellant, commencement of projectile movement? These things are not simultaneous, and again how would you practically measure any of these?

    Have you ever seen locktime given an actual value?

    Please give some examples of quoted locktimes and cite the references.


    By ukniels definition these things could be measured and given a numerical value (apart from the Wheelock), allowing proper comparisons to be made.


    The definition you support, while it might be linguistically sound, is, when examined, vague, very difficult to actually measure, and thus of no practical use.
    Last edited by Turnup; 25-04-2018 at 01:50 PM.
    True freedom includes the freedom to make mistakes or do foolish things and bear the consequences.
    TANSTAAFL

  14. #14
    Join Date
    Apr 2001
    Location
    Wet Cold Downtown Leicester
    Posts
    18,523
    Quote Originally Posted by Turnup View Post
    Can't see why anyone would be interested in how long it takes from trigger release to striking the primer - what use would this info be?
    Locktime is a function of the firearm itself, what happens after the pin hits the primer is a function of the cartridge.

    Very seperate issues
    A man can always use more alcohol, tobacco and firearms.

  15. #15
    Join Date
    Jul 2003
    Location
    Leek
    Posts
    383
    Quote Originally Posted by Turnup View Post
    Matchlock - not all have a trigger so when does the timing start?

    Flintlock and Wheelock - production of sparks?

    Flintlock and Matchlock and Wheelock, ignition of primer or propellant?

    What part of the propellant? (ignitions is progressive)

    How would you measure any of these anyway?

    Cartridge - strike on primer, ignition of part of primer, emergence of primer sparks into propellant, ignition of propellant immediately adjacent to primer, ignition of all of the propellant, commencement of projectile movement? These things are not simultaneous, and again how would you practically measure any of these?

    Have you ever seen locktime given an actual value?

    Please give some examples of quoted locktimes and cite the references.


    By ukniels definition these things could be measured and given a numerical value (apart from the Wheelock), allowing proper comparisons to be made.


    The definition you support, while it might be linguistically sound, is, when examined, vague, very difficult to actually measure, and thus of no practical use.
    What is your problem, it's not MY definition, just search lock time definition and you will find they all refer to hammer to propellant NOT ltrigger to barrel exit, nice article ishttp:// http://www.chuckhawks.com/locktime.htm which does include some timings.
    Of course it's hard to measure by us mere mortals but certainly possible, it's just as hard to measure the extra milliseconds for the bullet/pellet to exit.
    A lot of the time it is not measured anyway but improvements made that will speed it up, e.g. I've recently regged my AA400 and also made a longer faced hammer, lighter and delrin bushed, to shorten the stroke. This of course will shorten the time between pulling the trigger and hitting the valve, my locktime has therefore decreased, by how much I don't know or care but apparently every little helps in target shooting not that you'd know watching me

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •