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HOW TO ADJUST POI

Discussion in 'Uncategorized Threads' started by loophole, Sep 9, 2008.

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  1. loophole

    loophole TS Member

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    I have a KS-5 Special. It has an adjustable comb. butt plate, and rib. I would like to float the bird above the rib. Do you adjust the various items up or down to achieve float.
     
  2. baflstang

    baflstang Member

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    Raise the comb to raise the POI. Use your patterning board.
     
  3. jimrich60

    jimrich60 Member

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    Tschoenke:

    Since your shotgun has both an adjustable comb and an adjustable rib, first use the comb set the POI. Raising the comb will raise the POI, lower comb to lower POI. Changes in comb height of about 1/8in will generally change POI about 3 inches (gross rule of thumb) though each gun is a bit unique. Once you have the general POI set, you then use the adjustable rib to fine tune the POI. For instance, on my Beretta 687 Combo, raising the comb 1/8 in raises the POI about 3 inches. Changing the rib 1 mark or adjustment will change POI about 1 inch. So using the two areas in combo, it is possible (in theory) to change POI 4 or 5 inches say, rather than settle for 3, 6, 9, etc. Or even just 2 inches instead of the full 3. Just an example of what is possible with both adjustable comb and rib, each persons set of adjustments and perceptions of the POI will of course be somewhat different in actual use.
     
  4. zzt

    zzt Well-Known Member

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    Tschoenke, your gun works a little differently. You do not have a tetter-totter rib. Yours adjusts up and down from the front, and pivots at the rear of the rib. As such, you are better making POI adjustments with the rib rather than the comb. Your front and mid bead relationship stay the same. Essentially, you are pivoting the gun on your cheek. It is very easy to calculate the movement of POI with this arrangement.

    I don't know what the markings are on a KX-5, but if you are average height and build, moving the bead 1/8" up or down will move the pattern 1" for every 10 yards of target distance. It moves it in the opposite direction the bead was moved. So if you lower your bead by 1/8" your raise your pattern by 4" at 40 yards.

    When you run out of rib adjustment and want more than the 90/10 the rib will allow, raise the comb. The same measurement apply as for the bead adjustment, but in the opposite direction. If you raise the comb by 1/8" you raise the pattern by 1" for every 10 yards.

    So remember, lowering the bead raises the pattern, and raising the comb raises the pattern. Also remember, they work in conjunction with each other. If you raise the bead 1/8" AND raise the comb 1/8" there is no effect. The two actions cancel each other. If you LOWER the bead by 1/8" AND RAISE the comb by 1/8", the changes are additive. You have now moved your pattern by 2" for every 10 yards. That's 8" higher at 40 yards, and that's a big change.
     
  5. phirel

    phirel TS Member

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    zzt pointed out an important point. Adjusting the front of the rib will change the POI. But adjusting the rear of the rib will only change the sight picture and not the POI.

    Pat Ireland
     
  6. JBrooks

    JBrooks TS Member

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    First you will want to go to the patterning board and follow all the instructions in your KS5 book to try to set your point of impact. After you screw around with the rib and comb for about two hours and now have absolutely no idea what the hell is going on, try this:

    Make a circle on a piece of paper about the size of a $.50 piece and walked back about 13 yards. Use a full choke. Mount the gun and aim it directly beneath the mark about 12 inches and then smoothly bring the bead up until it touches the mark and fire. Reload and do this at least two more times. All three holes should be pretty much in the same place in relationship to the mark. This tells where you shoot the gun.

    If the holes are substantially off the vertical line yet your beads are lining up when you mount the gun, go see a professional stock fitter. If the holes are generally vertically aligned, measure how high the center of the holes are above the horizontal.

    In that the sure target kill pattern is probably about 22-24 inches at about 35-40 yards, to get your gun to shoot 100% high at 35-40 yards means that your holes should be about 4 inches high at about 13 yards. This is because 3 times 4 equals 12 which is half of 24 inches.

    Adjust the comb up or down until you get the three holes hitting correspondingly high above the mark to give you the pattern POI that you think you want. Of course if you want to "float" the target, I am not sure why you need any pellets below the target seeing as how the target is rising anyway.

    Now adjust the rib until you get the sight relationship between the mid-bead and the front bead that you want. Now go to the trap field, have the machine locked on straight and stand on post three. Start shooting targets. If the pieces fly up raise your comb. If the pieces fly down, lower your comb. If you're smoking the targets at 16, start moving back until you reach your handicap yardage. If you quit smoking the targets at any point raise your comb.

    If you'd like to shorten this process by two hours and avoid a lot of frustration skip the process in the first paragraph. Notice that I used "about" a lot. This is because we shoot shotguns. They have a pattern the size of a trashcan lid out at the target. About is close enough.
     
  7. comp 1

    comp 1 Well-Known Member

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    I have a ks5 special--adjusting the comb up and the rib down in front will make the gun shoot high---forget the stacking the beads junk--pattern the shotgun for poi and mount the gun by feel rather than stacking beads--you can change the poi by pressing your face down hard on the stock or by lightly placing your face on it beads stacked or not--my point is get the gun shooting where you want it when your face is on the comb in a comfortable position whether comfortable for you is pressing hard or lightly or with medium firmness--learn what feels right for you.
     
  8. hoggy

    hoggy TS Member

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    How does changing the rib do anything to change POI? If you NEVER looked at the rib and just moved the comb that would make you shoot either higher or lower or in other words change the POI. All the changing of the rib does let you see during setup how much or how little rib you see. Or how you see the figure 8. Only in bead watching (which is a no no) would the changing of the rib change the POI but that's not really a POI change. Or in other words change the comb to change POI or get gun to shoot where you look, than adjust rib to give you the look you want in setup.
     
  9. zzt

    zzt Well-Known Member

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    hoggy, that is not correct.

    JBrooks, if the beads are lined up and the barrels shoots left or right, you need a a different removable choke or a good barrel man, not a stock fitter.
     
  10. Hap MecTweaks

    Hap MecTweaks Well-Known Member

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    hoggy, when the front bead only is lowered, the eye also has to align/look lower at the bead also. I think I'd prefer an adjustable rib that lowered/raised at the front only compared to the center post rocking rib on many guns. Hap
     
  11. phirel

    phirel TS Member

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    The rear sight is the eye, the front sight is the end bead or the end of the barrel/rib. Changing either or these will change the POI.

    Pat Ireland
     
  12. mrcoachbob

    mrcoachbob TS Member

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    So, being new to this I am going to ask a dumb question. Should I remove the rear bead. Bob
     
  13. JBrooks

    JBrooks TS Member

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    Remove the rear bead if seeing rib between the beads bothers you. However, only do this after you are certain you can mount the gun consistently without having to align the two beads.
     
  14. JBrooks

    JBrooks TS Member

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    I recommended a stock fitter because he will be able to determine if it is a gun mount/technique or barrel alignment problem.
     
  15. RAScott

    RAScott Member

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    Allot of things that I read with adjustable ribs and combs, is adjust the rib to get you poi, and then adjust your comb to re stack the beads. left and right problems can be corrected by moving the comb to the right to move the poi to the right. and left to move it to the left.
    If you remove the mid bead then you are not sure that you are mounting the gun correctly every time. good book would be the "LITTLE TRAPSHOOTING BOOK" by frank little. he adresses the poi. in the first few chapters.
     
  16. JBrooks

    JBrooks TS Member

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    "Allot of things that I read with adjustable ribs and combs, is adjust the rib to get you poi, and then adjust your comb to re stack the beads."

    This doesn't work.

    "left and right problems can be corrected by moving the comb to the right to move the poi to the right. and left to move it to the left."

    This can work but your beads won't line up horizontally.

    "If you remove the mid bead then you are not sure that you are mounting the gun correctly every time."

    After a while you shouldn't need it.
     
  17. hoggy

    hoggy TS Member

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    Well as far I see it adjusting the rib/bead only changes the point of AIM not the POI. Unless you are aiming your shotgun like a rifle and using your front bead to aim at your bird. BTW I ran 50 straight today in Continental and never saw the front bead except in setup. I think that proves to me that I am right.
     
  18. Irfner

    Irfner TS Member

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    Have to agree with Hoggy. Only way to change to point of impact is bend the barrel or adjust the stock. Adjusting the rib front or back is just changing the view. You guys are not supposed to be looking at the sight when you shoot. Some of you even advocate its complete removal. Since I shoot one eyed and aim my shotgun like a rifle moving the front sight makes a great difference to me. But not in the point of impact which is the pigeon. It changes my sight picture or point of aim. I can either aim at the bird, above the bird or below the bird depending on my front bead position. But my point of impact is still on the target.
     
  19. Neil Winston

    Neil Winston Well-Known Member

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    What does Krieghoff say to do?

    Neil
     
  20. hoggy

    hoggy TS Member

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    All I really know is I adjusted my comb to get the gun to shoot where I look. I than adjusted the rib to give me a look down the barrle during setup that I could duplicate easily. As far as I'm concerned my POI is where I look when I shoot. Whether this is politically correct or not it does work for me.
     
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