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Point of Impact %

Discussion in 'Shooting Related Threads' started by butcher, Mar 4, 2010.

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  1. butcher

    butcher Member

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    If your gun is shooting 12 & 1/2 to 13 inches high at 40 yards what is the percentage? 80/20?
     
  2. zzt

    zzt Well-Known Member

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    Nominally, every 3" at 40 yards is 10%. So your gun is 90/10, or a touch higher.
     
  3. timb99

    timb99 Well-Known Member

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    It makes more sense to say your POI is 12 & 1/2 to 13 inches high at 40 yards.

    Percentage makes less sense.
     
  4. bigben

    bigben Active Member

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    Charger a gun that shoots 15 inches high is 100% which is considered a "neutral" gun incinerate em!
     
  5. phirel

    phirel TS Member

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    The above comments by zzt and bigben are correct if your pattern is 30 inches, but it is not 30 inches. I like timb99 suggestion but it might be more accurate to say that your gun just shoots high rather than attaching an incorrect number to how high.

    Pat Ireland
     
  6. Neil Winston

    Neil Winston Well-Known Member

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    To expand on Pat Ireland's post, it would be correct if:

    1. Patterns were square and

    2. Entirely evenly-distributed.

    However since they are round and hot in the center, the 3-inch equals 10% conversion is just for people who do not pattern. It's a meaningless bit of fluff, donned to put a bit of sparkle on an otherwise drab blouse.

    If someone says his gun shoots 80/20 you can be pretty sure he has no idea where it shoots. If, in contrast, he says he gun shoots 6 inches high at 40 yards, he probably has it least tried to find out, though, of course, he still may have no idea.

    Neil
     
  7. Hap MecTweaks

    Hap MecTweaks Well-Known Member

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    Where in the world did this pattern "percentage" thingie come from anyway? Inches high or low to the pattern centers makes much more sense to me, would to others too if they patterned enough!

    Hap
     
  8. waverider

    waverider Well-Known Member

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    I would guess it came from the guys like me that don't bother counting the holes in the pattern sheet. I just look at the pattern relative the Point of Aim and guesstimate the percentage above and below the POA. LOL

    Jason
     
  9. EE

    EE Banned User Banned

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    Neil, I think it would also be an accurate conversion if the pattern were rectangular (but still evenly-distributed). For a round, normally-distributed pattern, like shotguns shoot, the inches-to-percentage conversion is worthless.

    EE
     
  10. Mark425

    Mark425 TS Member

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    I thought...80%, 90%, or whatever meant....
    No matter what the yardage or pattern size, the percentage equaled how much of the pattern was above/below the point of aim.

    Example: 50% = 50% of the center of the pattern is above the POA and 50% is below the POA. 90% = 90% of the center of the pattern is above the POA and 10% is below it. In my mind it makes no difference what the yardage is as long as it is within reason. So a gun that shoots 90% high would have the center of the pattern about 13 inches above the point of aim, IF you had a 30 in diameter pattern. If you took the same gun closer to the pattern board, now pattern might be only 20 inches in diameter and the center was 9 inches above the point of aim, it is still shooting 90% high.

    The inches high means nothing to me. When you say your gun shoots 6" high, is that at 10 yards, 30 yards, 40 yards?

    Am I wrong? Could be...I was wrong once.
     
  11. ivanhoe

    ivanhoe Well-Known Member

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    Mark425


    "Am I wrong? Could be...I was wrong once."

    I think you better make that twice!!!!!! 90% of the pattern(pellets on the paper)above center has nothing to do with inches. Neither does 10% bellow.

    Bob Lawless
     
  12. Mark425

    Mark425 TS Member

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    Not the center...the POA.
    And... its all about math. Inches or percentage is the same thing if you will work it out. I have yet to read one article from a so called "top shooter" that said how many inches high his shotgun shot or gun manufacturer that uses inches. They seem to refer to percent and by percentage they dont mean number of pellets the mean a percentage of the diameter of the pattern.
     
  13. hmb

    hmb Well-Known Member

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    Inorder to solve this problem , you can purchase a pattern guage at your local Wal-Mart. HMB
     
  14. Hap MecTweaks

    Hap MecTweaks Well-Known Member

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    Mark425, ask Ray Stafford sometime. He'll tell you his gun patterns 32 inches high.

    Hap
     
  15. ivanhoe

    ivanhoe Well-Known Member

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    Mark425

    You said in your first post you said.

    "Example: 50% = 50% of the center of the pattern is above the POA and 50% is below the POA. 90% = 90% of the center of the pattern is above the POA and 10% is below it."

    Then you post what is below.

    "Not the center...the POA. And... its all about math. Inches or percentage is the same thing if you will work it out."

    Not the center what determines where the POA is the bottom pf the pattern paper or the top??? Why do you call it center in your first post if you now are call POA?????

    "They seem to refer to percent and by percentage they dont mean number of pellets the mean a percentage of the diameter of the pattern."

    What determines where the 50% or 90% comes from???? They mean the percentage of the diameter of the pattern. So tell us what determines the diameter of the pattern? Pattern of what?????

    BTW a little research will determine the answers to these questions.

    Bob Lawless
     
  16. Trap2

    Trap2 Well-Known Member

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    Mark425....... Read Frank Little's book, "The Little Book Of Trapshooting". We can both agree that Frank was, indeed, one of the"top shooters" of his day, can we not? He SPECIFICALLY states that his gun shoots 15" high at 30 yards. He goes on to explain the the % system means absolutely nothing when talking about POI. POI should always be in the amount of inches high at a set yardage... Dan Thome (Trap2)
     
  17. tcr1146

    tcr1146 Well-Known Member

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    Cut out the shit Neil! You know exactly what is meant by 60/40, 70/30 etc! The gun manufacturers do not quote inches, they quote %! So please lower yourself long enough to explain to this poster what he wants to know! Tom Rhoads
     
  18. Mark425

    Mark425 TS Member

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    Hey...love everyone here, dont want to fight with you guys.

    The point I was trying to make is percentage and inches are exactly the same thing.

    Look if you will tell me how high (in inches) your gun shoots and the size the pattern, I can tell you the percentage. Just as if I tell you how many percent high my gun shoots and the size of the pattern, you can tell me how many inches high it shoots.

    Peace everyone,
    Mark
     
  19. Neil Winston

    Neil Winston Well-Known Member

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    Gunmakers and the like use percent so you can never catch them at it, Tom.

    Scenario 1: I get a gun, open the instructions, and it says the second line, paired with a blue spacer, will be an 80/20 pattern. I go out with it set like that and it shoots about two inches high. Do I have grounds for complaint? Who knows, as long as there are (at least) two definitions of percent high, one of which is total BS and that's the one everyone uses.

    Scenario 2: I get a gun, open the instructions, and it says the second line, paired with
    "stacked beads," will put the center of the pattern eight inches high at 40 yards.
    I go out with it set like that and it shoots about two inches high. Do I have grounds for complaint? Maybe so, or at least you can catch them saying that their stated precision "within their manufacturing tolerances" is about worthless and at least tell your friends.

    Do I know "what is meant?" Sure, and in some cases, I know that people who think they mean something are simply wrong. Let's look at the difference between 12 inches high and 15 inches high. Convention says the former is 90%, the latter, 100%. In reality, they are almost the same. Very, very few pellets are moved when you go from 12 to 15 inches. In fact as I look at a pattern here, fewer than 10 pellets are actually moved from below the point of aim to above it when you raise the center from 12 to 15 inches. That's not ten percent, that's a couple of percent. In the other extreme, the density and width of a pattern at its center means that when you go from 0 to 3 inches high, you move a ton of pellets, way more than 10%.

    I repeat, "percent high" is a scam. If you _know_ the correct number, there's no excuse for substituting the right one - inches - for what is almost certainly the wrong one, percent high. If you don't know where your guns shoots, go ahead and lecture us on the "percentage of its charge it places above the point of aim." Everyone else does and they don't know either. Just don't ask us to take you seriously; that's all.

    Neil
     
  20. Mark425

    Mark425 TS Member

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    Alright Neil. I get your point. Well said.

    Anyway, when I checked my gun a long time ago it shoots about 11 high at 40 yds and about 6.5 at 20yds, at least thats what I have written down. Works OK for me, now I just need to point better.
     
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