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poi question

Discussion in 'Uncategorized Threads' started by smsnyder, Sep 21, 2007.

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  1. smsnyder

    smsnyder Well-Known Member

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    i pattern a kolar unsingle at 32 yards and it shoots 18 inch high dead center above reference point with a figure 8 sight picture. now, i shoot o/u barrels at same yardage with same sight picture (figure 8) and bottom barrel is about 70/30% and top barrel is about 60/40. how is this possible with both sight pictures the same. huge difference. thanks
     
  2. AAtrap

    AAtrap Well-Known Member

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    smsnyder, I check point of impact at 13 yds. You stated bottom bbl at 70/30 bottom bbl.at 60/40. ok , see you caught it while I was typing. LOL
     
  3. smsnyder

    smsnyder Well-Known Member

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    both patterns in o/u barrels have pellets in reference point and above. the unsingle barrel pattern is not even close to the o/u barrels. i like the patterns but i was wondering how this is possible with both having the same sight picture? My comb is all the ways down on both barrels. I shot 5 patterns each from all barrels. off sand bags. there should be no difference between 13 yards and 32 yards. both should give the same results.
     
  4. smsnyder

    smsnyder Well-Known Member

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    i do well with the high poi on the unsingle barrel. my average has increase from about 84/86 to 91/93. in caps and singles. i had no idea that all barrels could shoot different impacts. how and the heck to you get them to all shoot the same? 18 inches high in the unsingle vs 5/6 inches high in o/u barrels is a huge difference.
     
  5. smsnyder

    smsnyder Well-Known Member

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    i knew there would be some difference in unsingle point of impact vs o/u point of impact but not this much difference. there is no way to get the o/u barrls to shoot 18 inches high (110%) like the unsingle barrels. i like the way it shoots but just wondered how it is possible.
     
  6. smsnyder

    smsnyder Well-Known Member

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    neil are you out there. perhaps you can tell us how this happens? i would figure that one of the o/u barrels would shoot the same pattern height as the unsingle barrel with the same sight picture. not so.
     
  7. GunDr

    GunDr Well-Known Member

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    It could be possible that the sgl bbl is not straight. There are no "mid hangers" on the unsgl, so the bbl could be "sagging" a little in the middle. Taking a measurement over the front sight of both bbl's to the inside of the choke, if both are the same should shoot quite close.

    With a K-80, it's possible to have different POI's with the same sight picture, because the bbl moves, not the rib.

    Any gun that has a movable RIB, should shoot relatively close to it's O/U mate.

    Remembering the first 400-500 guns I work with and patterned while still at Kolar, the Under bbl's, being adjustable by changing the front bbl band, did shoot a little higher that the top bbl's. My understanding was that many shooters preferred this set-up (I know I did).

    I would contact Kolar and have them pattern the bbls and dial indicate the bbl for straightness.

    Doug
     
  8. phirel

    phirel TS Member

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    smsnyder- First, the advantage of checking the POI at 13 yards is that it is much easier to identify the center of the pattern. At 32 yards, it can become difficult to point to the exact center of the pattern.

    In a fine gun like you have, your three barrels are reasonably straight and fairly round but they are not identical. You stated that you shoot five patterns from each barrel. This should convince you that the same load shot from the same barrel will not always do exactly the same thing. I have seen instances where simply changing the choke tube in one barrel will result in a change in the POI.

    You are getting into pattern performance and analysis. The deeper you get into this area, the more confusing things become. Random events are difficult to analyze.

    Pat Ireland
     
  9. maclellan1911

    maclellan1911 TS Member

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    I agree with Pat. It took me a few sessions to really get it. I thought my barrels on my XT where out of wack. A few good days on a gun vise and bench proved this out. Then it was off to checking chokes and adjusting comb ect ect. Maybe a trip back to kolar is in check if indeed barrels are off. Are the O/U barrels the same length. I dont know about shot guns but 2in differance in a sight radius on a pistol is huge. My thinking is if the center bead on both guns is in the same place, moving the front bead forward would raise poi? if the center bead is in a different location you would end up with results also? No exspert here. Anyone know if what I think may be true?
     
  10. Beretta687EELL

    Beretta687EELL Well-Known Member

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    SM, The Kolar O/U barrels POI can be adjusted. The front barrel hanger and mid barrel wedge can be changed. The combination of these two items determine the POI of each barrel. Call Keith Spranger at Kolar and he can fill you in on the details, like he did me. Bill Malcolm
     
  11. smsnyder

    smsnyder Well-Known Member

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    thanks, i am not concerned about poi. i like the unsingle shooting 110% high. there is nothing wrong with the over under barrels they just don't match the high impact of the unsingle and that's ok. i just have to adjust alittle on double shooting. the bottom barrel shooting 70/30 is ok due the first target in doubles rising so fast. the top barrel shooting 60/40 is ok also because the second target in doubles is often flat. i just didn't know that a combo set poi will vary so much. in this situation it works to my advantage. thanks
     
  12. smsnyder

    smsnyder Well-Known Member

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    by the way unsingle barrel is 34 inch and o.u barrels are 30 inch.
     
  13. phirel

    phirel TS Member

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    If my arithmetic is correct, due to gravity, the 30 barrels would print 0.002 inches lower than the 34 inch barrels. This has nothing to do with the question posed but it is common on this site to see posts that are irrelevant.

    Pat Ireland
     
  14. ivanhoe

    ivanhoe Well-Known Member

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    smsnyder I don't know if my information is correct or not but I think the unsingle on the Kolar has an adjustment on the front of the rib. I believe someone that owns one said that it is the same type as the K-80.

    If this is so then the rib/barrel is adjusted to shoot high. If this is so then that is the difference in relation to your question "how is this possible with both sight pictures the same."

    Bob Lawless
     
  15. Hap MecTweaks

    Hap MecTweaks Well-Known Member

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    Earl, if you were to measure your over/under at the back and front and compare that measurement to your un-singles numbers, you'd see how it shoots so much different. Measure from rib to center of chambers/barrel ends at front and back. On the un-single, the numbers will have a greater variance between the front and rear even though the sight alignment is the same "look". Hap
     
  16. smsnyder

    smsnyder Well-Known Member

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    thanks , that interesting. another lesson learned on trapshooters.com
     
  17. hairy

    hairy TS Member

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    Earl, if I where you I'd lower the single barrel down to what you say the 0/U is shooting and learn to shoot it there. In my opinion there is never a reason to shoot a 110% high gun for 16's, and those AAA shooters who do, only do so because they want the POI for shooting 27 yard handicap.
     
  18. phirel

    phirel TS Member

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    hairy- I see nothing wrong with a gun that shoots that high. Keep in mind that checking the POI only tells you where the gun shoots. It does not indicate where the shooter shoots the gun. My gun will pattern about 100% high but I shoot it where I am looking when I remember to keep my head down. Checking the POI from a rest is very different from shooting on the line.

    Pat Ireland
     
  19. hairy

    hairy TS Member

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    Mr Ireland, when I check my gun for POI, I do so with the same sight-bead reference I use when I'm shooting a target, and I expect the POI to be the same.

    I just think Mr. Fairman....a fairly new shooter, 20 yard - class D, would be much better served with a lower shooting gun. I saw him shoot at Sparta and he shoots far too fast and that might be what makes him think he needs a high POI. He doesn't...what he needs to do is slow down, point the targets out, and it would be much easier for him to do that with a lower impacting gun.
     
  20. Dove Commander

    Dove Commander TS Member

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    Hairy, Let the shooter determine his point of impact. Everyone's bird to bead relationship is differant. Length of barrel, weight, loads, and choke all play a part in this. The shooter needs to figure this out. Early, I lost a couple of years by listening to the wrong people. It's actually all worked out using common sense and practice, practice, practice. At the end of the day, consistancy, is the key.
     
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