Believe the Target Episode with Jim Borden

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  • Jun 15, 2020
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    What did everyone think about the latest "Believe the Target" episode with Jim Borden and Erik Cortina?

    Has anyone done any testing on the actions that are popular in PRS as far as which actions for the most consistent fire control systems, ignition?
     
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    I’m not sure to be honest exactly what methods could be used to measure ignition consistency other the the target which the result on the target has so many other variables stacked in with it

    I am sure there are more experienced and knowledgeable people in this area that can add how they determine the quality of ignition in a high precision rifle for PRA or f class or Bench rest

    Maybe checking the firing pin spring for binding

    Maybe checking the cocking piece clearances that the clearances are not overly big or small
     
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    There is a good opportunity for someone to do a graduate level thesis studding, testing and evaluating ignition systems. Currently most of the information moving around is based on empirical science, rather than actual numbers.

    There are so many things that we still need to understand what results in consistent ignition and how much each variable is contributing to it. For me personally, the biggest thing I would like to learn is, do we actually care about:
    • Spring rate.
    • Striker travel.
    • Striker weight.
    Which everybody is talking about all the time when they talk about consistent ignition

    Or should we actually care about:
    • Spring work (Joules).
    • First derivative of spring work = Spring power = (dW/dt) = (watt or Joule/Second).
    I also admire people spending a lot of time, tweaking various components to reduce drag, however, I do find the upward angled sear of the Remington 700 platform the elephant in the room when it comes to drag.

    Another very important thing to keep in mind is, just because a certain ignition characteristic is good for one shooting discipline, doesn't mean it is the best for all other disciplines. To give an example; We as shooters might be tempted to copy what ever ignition bench rest shooters are using, because they are shooting the smallest groups by far. However, their rifle is held very rigidly, thus the crosshairs are not moving at all when they release the shot. Thus they can play with heavy ignition systems that have a long lock time. In PRS, the crosshair or the target is not standing still, thus a lighter ignition system might be more beneficial, even if it results in less ignition consistency.

    My opinion is that until somebody takes the time and effort to get real numbers, ignition will remain a dark art where one day we will be told a certain thing is best, then the next day another, chasing our tails endlessly.
     
    I haven't done a search yet, but might be worth checking DTIC. I imagine there's been non-public facing research into this as well, especially as it's related to action time - which is measured when qualifying guns/ammo to Nato EPVAT.

    Being that EPVAT does include measuring action time, you should in theory be able to relate the firing pin strike, indentation depth etc. to the pressure curve, especially if you were to run a test with just a primed case.
     
    There is a good opportunity for someone to do a graduate level thesis studding, testing and evaluating ignition systems. Currently most of the information moving around is based on empirical science, rather than actual numbers.

    There are so many things that we still need to understand what results in consistent ignition and how much each variable is contributing to it. For me personally, the biggest thing I would like to learn is, do we actually care about:
    • Spring rate.
    • Striker travel.
    • Striker weight.
    Which everybody is talking about all the time when they talk about consistent ignition

    Or should we actually care about:
    • Spring work (Joules).
    • First derivative of spring work = Spring power = (dW/dt) = (watt or Joule/Second).
    I also admire people spending a lot of time, tweaking various components to reduce drag, however, I do find the upward angled sear of the Remington 700 platform the elephant in the room when it comes to drag.

    Another very important thing to keep in mind is, just because a certain ignition characteristic is good for one shooting discipline, doesn't mean it is the best for all other disciplines. To give an example; We as shooters might be tempted to copy what ever ignition bench rest shooters are using, because they are shooting the smallest groups by far. However, their rifle is held very rigidly, thus the crosshairs are not moving at all when they release the shot. Thus they can play with heavy ignition systems that have a long lock time. In PRS, the crosshair or the target is not standing still, thus a lighter ignition system might be more beneficial, even if it results in less ignition consistency.

    My opinion is that until somebody takes the time and effort to get real numbers, ignition will remain a dark art where one day we will be told a certain thing is best, then the next day another, chasing our tails endlessly.
    Excellent point about lock time importance depending on different styles of competition
     
    It
    I didn't watch the video but Alex Wheeler has been talking about improving timing and ignition for years.
    has he talked about what measures or steps he takes when he builds an f class rifle or a hunting rifle to improve ignition consistency over what could be done by a guy buying an action, a prefit barrel, a tt diamond, a chassis and starting shooting?
     
    Besides “ignition consistency“, an other accuracy factor is striker inertia and bolt movement. A loose striker bouncing inside the bolt, and the bolt moving in receiver bore when the trigger bar falls, impart some vertical and lateral impulse to the action. Also what Speedy and Jim Borden said about the bottom of the striker bouncing on the sides of the way in the action.

    Dry firing different rifles, in a front rest and bag, movement of the bolt can be seen. Looking thru a high mag bench rest scope, rifle disturbance can be seen, where the POA moves to when the striker has fallen. Borden builds actions that are very tight concentricly. Ideal for bench rest and f-class.

    I have a Neseka Bay action with “Borden bumps”. I think Jim Borden had an important influence in the design of that action, and it has by far the smoothest firing pin fall of any rifle I’ve had. Touching the bolt and rear bridge, or the bolt handle, when the striker falls, no movement can be felt.
     
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