POI change with lumenkocks

Discussion in 'Bowhunting' started by BlackStreak, Jul 15, 2012.

  1. BlackStreak

    BlackStreak Active Member

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    I've noticed that when I shoot a broad head along with a Lumenock my POI is low as if I was 5 yards farther back. Broad heads with my regular knocks shoot identical with the field tips. Field tips with lumenocks are hitting dead nuts. Only when I combine the two does my poi change. Is this just my isolated problem?
     
  2. bamadawg2009

    bamadawg2009 Well-Known Member

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    NOPE Mine do the exact same thing I think they say lumenoks weigh aout 3-5grains more than a regular nock does, so it will change.
     

  3. c_bass16

    c_bass16 Well-Known Member

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    I don't see any difference inside 45 yards when only the nocks change. Past 50, there seems to be a slight difference.

    My broadheads cause way more POI change than my nocks do. I do notice it when I use them both though, but I attribute more of that to the broad heads.

    G5 125 Striker Magnums have a pretty large wingspan though, so drag was to be expected. With a mechanical that are designed to fly like field points, I can see how you'd notice, although my groups probably aren't tight enough to make it all that obvious.

    I usually practice for (shoot at) 2" at 20, 3" at 30, 4" at 40...on out to 80 (7 pins)
    Farthest on a deer is 67m...farthest on a paper plate is 90m.
     
  4. marinetowgunner

    marinetowgunner Well-Known Member

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    I'm shooting carbon express blue streaks with their lighted nock and have 0 POI shift with field tips and g5 strykers. Is this only with Lumenock that ppl are seeing the shift?
     
  5. marinetowgunner

    marinetowgunner Well-Known Member

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    I bought a set of lumenocks just to try them out and I am shooting low now as well. Must be because of the weight of the lumenock.
     
  6. Supermag

    Supermag Well-Known Member

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    The weight of the Lumenoks is not only add weight to the arrow (about 15 grains for "X" nocks like the Full Metal Jacket and Axis arrows use) but put it at the back end thereby reducing your Front of Center weight distribution.
     
  7. 41mag

    41mag Well-Known Member

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    That is it in a nutshell right there.

    Even slight changes will effect the dynamic spine of your arrow as well, which can also throw it off a little bit. If your shooting light for poundage spined arrows it will show up more readily than if shooting a bit heavier spined one as well.

    My friend and I spent a couple hundred dollars, and several months, trying out all of them in several different combinations of fletching, shafts, draw weights, and came to the conclusion that the Nockturnal effected things the least, stayed in better, and lasted longer than any of the others.

    That said, I shoot several different bows with different arrows and haven't found the Nockturnals to change much if anything out to 50yds. Even with my lighter Carbon Express arrows shooting from my Drenalin at 70# they still will hit the ear plug with boring regularity if I do my part.

    IF you can find some Nockturnal's or order a package, you might even contact them to see if they will send you one to test, I think you would be better off with them, and probably not see quite as much change if any with your set up.

    When I say not much of a change, we shoot ear plugs which we stick into our targets, trust me when I say you see a change no matter how small,

    two 3 shot groups, two bows same arrows @ 40yds,
    [​IMG]

    I thought I had this showing the lighted nocks, but this was all I got. I don't do groups very often because I end up breaking arrows, that was why we went to shooting the ear plugs. That's also why there aren't any FMJ's in those groups too. It only takes hitting one, to ruin two of them, and that gets expensive fast.
     
  8. BlackStreak

    BlackStreak Active Member

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    I agree with you. I went from using luminocks to nockturnals and was hitting pretty close to the same POI that my regular arrows do. Even better is that the nockturnals hardly ever fail to light and stay lit. Only when the nockturnal is filled with blood and the blood is not flushed out, will the nock have a tendency to fail. Guess the salinity of blood eats or corrodes the circuitry in them. I've learned to cut the too off a small needle and use the needle and syringe filled with water to flush the blood out. Just soaking it in water doesn't remove the blood. Since I've started removing the blood the blood from the inside of the nockturnal, I've never had a reused nockturnal fail to perform just like a brand new one.
     
  9. coyotemaster

    coyotemaster Active Member

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    I am not familiar with the OD at the back of the lumennocks but I know from tuning experience that even a slight degree of difference will affect broadhead flight. In effect if the diameter is larger than your previous knock you are changing knock height just a tad and with a broadhead that causes difference in hi-lo on target. You may want to try raising your rest setting just a bit to compensate for diameter difference in the knock. I see the logic in the FOC argument but that is a big change for a few grains weight difference.
     
  10. specialist

    specialist Member

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    Nov 5, 2012
    sometimes the tightness of the the nock on the string changes poi, and how it sets on the rest.
     
  11. 1/2 slam

    1/2 slam Well-Known Member

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    Oct 10, 2009
    Interesting post. I may have to try some nockturnals, I was never happy with the lumenkocks. always had trouble with them coming off or not lighting.