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An odd speculation about adjustable ribs

Discussion in 'Uncategorized Threads' started by Neil Winston, Sep 29, 2007.

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  1. Neil Winston

    Neil Winston Well-Known Member

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    The moderator has received substantiation that Buzzgun has successfully completed his anger management therapy and so has permitted me to post this.

    I see MX-10 (and similar) users adding spacers to their combs as they move from singles to handicap. Almost no one will disagree that they will see more space between the beads and the gun will shoot higher. (Well, _someone_ will disagree, this is TS.com after all, but some things just can't be helped.)

    Say I got one and wanted it to shoot higher at handicap as do so many of the others. (In fact I don't, but say I do just for the purposes of this single post.) So I do whatever I need to get the handicap POI where I want with a "stacked-bead" view. But then rather than doing anything with the comb, I tilt the rib, higher in front, lower in rear. It should shoot lower, shouldn't it? (This is about where Buzz will start calling his sponsor.)

    So what's odd about this? I may be wrong, since I don't have one to test it on, but haven't I wound up with a lower-shooting gun with _more_ visual space between the beads? How did this happen?

    This is a serious question.

    Neil
     
  2. ec90t

    ec90t Guest

    Neil,

    If I shot the gun the way you mentioned it being set up. I would be shooting off the end of the barrel. This is just the sight picture that I was seeing when I shot an MX3 and MX6 a couple of weeks ago. I couldn't tell you if they shot low or high, because I was fixed on the target and not the beads. I managed to hit the targets, but wasn't very impressed with either gun.

    Unless you shoot an older K-80(pre trap special) or KS/X-5, you set the POI with the comb and then adjust the rib to get the desired sight pattern. I knew a shooter once that did the same thing with a fixed rib gun. He epoxied a mid bead on to some threaded stock and used a jam nut to tighten the bead. He could then adjust the height of the bead to get the desired sight picture once he set his comb.

    ec90t
     
  3. phirel

    phirel TS Member

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    Neils hypothetical gun would shoot lower with more space between the mid and front sight. I believe his point is that the space between the mid bead and the front sight has nothing to do with the POI. That space is a result of the comb height in relation to the front sight. Raising the comb does increase this distance, but it is the comb height that alters the POI, not the space between the sights.

    Pat Ireland
     
  4. Jerry944t

    Jerry944t Well-Known Member

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    It will shoot exactly the same no matter the position of the rib. The only variable is the height of the comb which determines the rear sight position (your eye). Assuming that you don't try and get the beads aligned and assuming that the front bead doesn't move, which it doesn't in these guns the rib can be placed in any position with no effect on POI.

    It seems to me that the only reason for a variable rib is to bring most people into their comfort zone of having the beads close to that magical and fairly useless figure 8.

    Smash Em,

    Jerry
     
  5. Neil Winston

    Neil Winston Well-Known Member

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    Buzz is about to wander in with a beer can, put it on the rib, mount a bead on it, and have you tell him, Jerry, that it won't shoot lower. That's before he gets into substitutable front sights on Olympic rifles, which he considers "trump."

    And I agree. If the front bead is farther above the centerline of the bore, as it is when you lift the front of the rib and lower the read, then it must shoot lower.

    Pat, I can't see how you can write "Raising the comb does increase this distance, but it is the comb height that alters the POI, not the space between the sights." when I have altered the point of impact, as you agree, and I haven't moved the comb.

    Neil
     
  6. Jerry944t

    Jerry944t Well-Known Member

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    Neil, you are correct. The bead on my Perazzi is mounted on the rib not on the front post as I thought. So moving the rib higher would increase the distance between the front bead and the centerline of the barrel thus, all other variables being equal the gun will shoot lower.

    Jerry
     
  7. Neil Winston

    Neil Winston Well-Known Member

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    No, I'm not jerking anyone's chain at all, Gregg, and I thank you for your first-hand account of how yours works.

    But I'll tell you, I still don't get it the argument all of you are making, but the whole thing seems to be messed up with that center-bead thing. So let's take if off for clarity. My original post is now to read:

    "Say I got one and wanted it to shoot higher at handicap as do so many of the others. (In fact I don't, but say I do just for the purposes of this single post.) So I do whatever I need to get the handicap POI where I want. There's no middle bead on this one, so I just moved the comb up and down until I thought the POI was where I wanted it. I see some rib, but don't "match it" with anything in particular. But then rather than doing anything with the comb, I tilt the rib, higher in front, lower in rear. It should shoot lower, shouldn't it?

    Now it's clear. I want to aim with the front sight and put it in a particular vertical relationship with the bird.

    Neil
     
  8. Paladin

    Paladin Well-Known Member

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    The gun would shoot lower because the barrel was lowered away from the front bead.




    This is all providing the comb height is not changed.



    There are only three vision points involved here. Eye, front bead and target. Starting with eye, which is at your predetermined height. The eye looks to the target and you bring the front bead to the target. The distance from the front bead to the muzzle is the determining factor if the pattern will shoot high, dead on, or low.




    Stacked beads are not a true indicator of a good handicap setup, if you're using rib adjustment to change to a handicap setup.
     
  9. phirel

    phirel TS Member

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    Neil- I intended to say that raising/lowering the rear sight, the eye, by adjusting the come or raising/lowering the front sight can change the point of impact. Both the front sight and the comb/eye can be changed independently. I used the comb in my first response because altering the distance from the front sight and the barrel requires a lot or work. The only practical way to do this is by changing the rib posts or using an add on rib. A superficial examination of my K-80 might result in someone incorrectly concluding that the front sight moves.

    Pat Ireland
     
  10. Neil Winston

    Neil Winston Well-Known Member

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    Pat, altering the distance between the front sight and the barrel on my example MX-10 requires no work at all. Or at least that's the way I understand it. You just slip the spring-loaded locking-clip back, move the rib, and let go of the clip (and hope it stays, which I've heard doesn't always happen.)

    Neil
     
  11. Barry C. Roach

    Barry C. Roach Well-Known Member

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    pivot point on gun please?
     
  12. Barry C. Roach

    Barry C. Roach Well-Known Member

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    pivot point on gun please?
     
  13. Neil Winston

    Neil Winston Well-Known Member

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    In the middle, I think, Barry; I can't see it working right any other way.

    Neil
     
  14. superxjeff

    superxjeff Active Member

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    Just remember Buzz whenever two or more are gathered we have a meeting. Some of us have a meeting of the minds and the rest of us will just have a meeting. Ha-Ha Jeff
     
  15. Paladin

    Paladin Well-Known Member

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    Neil,

    The "stacked bead view" and some barrel visible between the beads, is the view you would be looking for if you were adjusting with the comb, for a higher point of impact.

    It's not the view you would be looking for if adjusting the rib for handicap.
     
  16. fearlessfain

    fearlessfain TS Member

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    just think, when i started shooting trap 45 years ago all anyone talked about was "lock tlme" (no back boring,forcing cone work,removable chokes, release triggers,expert tuning, etc.) and we shot just as well with trap guns that kooked like shotguns.
     
  17. fearlessfain

    fearlessfain TS Member

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    my proof reading is bad today.
     
  18. fearlessfain

    fearlessfain TS Member

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    my proof reading is bad today.
     
  19. Neil Winston

    Neil Winston Well-Known Member

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    Paladin, I don't understand.

    Neil
     
  20. Neil Winston

    Neil Winston Well-Known Member

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    John, that's clear and correct, at least as far as I can understand it. It's why I removed, verbally, the mid-bead about mid-thread. Wie du sagst, es macht nichts aus, weil es kein einfluß hat.

    Neil
     
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