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How do I find my Point of Impact?

Discussion in 'Uncategorized Threads' started by Newport 90T, Apr 10, 2007.

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  1. Newport 90T

    Newport 90T TS Member

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    What is the best way to determine the Point of Impact on my 34" Model 90-T?

    Fred G.
     
  2. Mac V

    Mac V Guest

    Put a 4-inch red dot on the side of a piece of a refrigerator box. Go to a range and prop the cardboard up on the ground about 30 yards away from you. Sitting at a bench with the gun supported on sand bags, loaded with your usual trap load and the correct choke, obtain your normal bead picture on the circle and pull the trigger. The cardboard will tell you waht you want to know.

    Mike
     
  3. phirel

    phirel TS Member

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    Mike- I do not agree with your method. The POI can not be accurately determined from a 30 yard pattern without using a computer program. It is not possible to accurately determine the center of the pattern shot at 30 yards by just looking at the pattern.

    POI is best measured at 13 yards using a rest. Also, shoot at least 5 shots and 10 is better.

    Pat Ireland
     
  4. Neil Winston

    Neil Winston Well-Known Member

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    Like this, Fred.

    Neil
     
  5. Rollin Oswald

    Rollin Oswald Active Member

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    Fred,

    While patterning to find your POI, you will be aiming your gun like a rifle and the results will be valid. You must realize that those results will be valid ONLY with your eye in that exact position relative to the rib.

    If your head moves on the stock during swings as is common if either your shooting form or stock dimensions are incorrect, the POI will also change.

    If you reread MAV V's response above, you will notice that he wrote "...obtain your normal bead picture on the circle and pull the trigger." It is the ability to "find the normal bead picture" that is the challenge because you will not know if your head has moved on the stock when shooting at moving targets. If it has, you will have deviated from "the normal bead picture".

    Rollin
     
  6. JGS

    JGS Member

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    Pat, I've heard that one should determine the POI at 13 yards as you suggest, and I've heard that the proper distance is 16 yards. It would seem that the formula used to determie pattern density above and below the target at 32 yards, i.e., one inch high equals 60/40, two inches high equals 70/30, etc., would be impacted by the distance used. Any thoughts on this? Perhaps three yards are a difference that don't make a difference. Thanks.
     
  7. Mac V

    Mac V Guest

    Pat,

    Checking "point of impact" is exactly that...checking to see where my shot charge will impact the target when my body and my gun are related as they should be.

    My concern when I check my gun's point of impact is...what will the shot load look like at the target. If I'm going to be hitting targets that are 30 to 35 yards away from me, patterning my gun at 13 yards is simply primer testing. It tells me nothing useful about the shot position and distribution at impact. It's only valid if I want to shoot out the light on the back of the trap house.

    Mike
     
  8. powder-em

    powder-em Member

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    Mac V, You should listen to Pat he is right. At 13 Yds. your shot pattern is very tight and will break the paper in a small circle. Where this small (out of round) circle hits in respect to your point of aim is what you need to know. If you aim at a dot and hit several inches high you know you are to high. If you drill out the dot you are flat or 50/50. I like about an inch or so high. IMHO. Dave
     
  9. W.P.T.

    W.P.T. TS Member

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    Pat Ireland told you the right way and Neil Winston backed it up ... This is the absolute correct way to do what you asked for ... If you are looking for checking your pattern, its a waste of time because no two shells are exactly alike and you will get variations of the same thing over and over again ... The hole that might exist in one pattern probably won't in another or if it does won't be in the exact same spot ... I check for Point of Impact (POI) only, but there are others who like to look at and count all the little holes in paper or use an overlay to see how good or bad the pattern of that particular shell is or should I say was ...? WPT ... (YAC) ...
     
  10. Mac V

    Mac V Guest

    It's not a matter of whether Pat or Neil is right or wrong; it's a matter of whether I can interpret what I see well enough for it to be of use to me. I tried the 13-yard thing and what I got was a splatter of pellet holes offset a bit upwards of a 2-inch dot. Great! Now I know the gun shots a bit high of my aim point. So what does that translate into as far as determining how much under the target to swing at a hard right target? Damned if I could figure that out from looking at 6 pieces of cardboard with 6 splatters on them, no two of which had the dot in the same place.

    I found it much more useful to set a big piece of cardboard out at same distance from me that a target would be when I pulled the trigger, put a bird-size image on it and adjust things until I got the majority of the shot to hit where I wanted it to when I pointed where I wanted to. I know the patterns will be different; I don't care about the pattern as much as I want to know where the majority of the shot hits when I point the way I want to.
     
  11. phirel

    phirel TS Member

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    MAC V- You stated that when you 6 different points at 13 yards, you got 6 different points of impact. This tells us that you jerked the gun when pulling the trigger or you have a very serious problem with the gun. If one shoots 10 different targets at 13 yards, 7-9 should be in the same place. The 2-3 stray points of impact represent shooter error.

    If your true POI is 1 inch high at 13 yards, your gun shoots approximately 60/40 at 35 yards. Two inches high at 13 yards is approximately 70/30 at 35 yards. Scattered points of impact at 13 yards as you experienced need to be investigated quickly and throughly.

    Pat Ireland
     
  12. Mac V

    Mac V Guest

    OK guys...I'm not going to argue the point any longer.

    I never sighted a rifle at 200 yards and then tried to extrapolate and figure out where it would hit at 1000 yards. I never learned to extrapolate. I sighted the rifle at the distance(s) I expected to use it and I see no reason to do any different with a shotgun. If you can tell how far up the center of a 10-inch shot splatter has moved when the comb is raised 1/16", you're better men than I. My method is not by the book, but it tells me what I want to know.

    Mike
     
  13. djpk69

    djpk69 TS Member

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    Tightest choke?
     
  14. Frenchy

    Frenchy Member

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    Old 90T
    If you are looking for your POI here is what the best barrel man in the business told me, that would be Stan Baker ( in my humble opinion),he started this 30 years ago.You will see that this is very close to what other people have explained to you,he told me to do this before I started serious competition with any gun I purchased,if the barrels are not true you will never know your true potential.First get a empty target box,put a clay target in the center and completely blacken it in with a magic marker.Second warm up the barrel,shoot a round of trap or (god forbbid)skeet,then place the target box 15 yards away (45feet) and with the fullest choke you have bench rest the gun like rifle shooting from a rest,your aiming point is 6 o'clock on the black dot.You shoot 3 shots,you should completely take out the black dot,if you do your barrel shoots true,this also goes for the over under barrels.If the barrels do not shoot true you should think about another barrel or replacing the gun with another,hopes this helps.
     
  15. lumper

    lumper TS Member

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    Have you looked for it at the lost and found?
     
  16. comp 1

    comp 1 Well-Known Member

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    90t,step back 35 yards from your target;should be at least 4 feet square with a 4 inch aim point drawn on it slightly below center. Shoot three or four shots at the target offhand just as you would a real target. Don't press your head down real tight and take careful aim at the target;just put your gun in position and point the bead or end of barrel at the bottom of the target[aim point],relax and fire.. if the overall pattern/p.o.i. is equally distributed above and below the aim point the gun is shooting flat or 50/50--raise your comb an inch or so and try again until you get it printing so that there's about 2/3's above the point and 1/3rd below----then go shoot trap and see how you do.
     
  17. perazzi03

    perazzi03 TS Member

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    i just stepped off 15 to 20 paces, shot at a dot on paper, pattern was about 75% above the dot.went to the owners manuel, it says for the way i have my rib set im shooting 70/30. not hard to figure out. if thats not correct i dont care cause i brake the targets
     
  18. phirel

    phirel TS Member

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    irfner - The basic problem is that the true center of a pattern shot at 40 yards cannot be determined by simply looking at the pattern. The center of the pattern can be accurately determined at 13 yards.

    Pat Ireland
     
  19. Neil Winston

    Neil Winston Well-Known Member

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    rhmt, that happens to people all the time. But it's only because people let it.

    As I said in another thread, for some reason successful and critical people simply shut off their common sense when they go trapshooting.

    OK, so this fitter told you that shooting off a rest would not give you consistency and so you should stand and slap the trigger instead. That makes no sense. You bought it because he's made stocks for the stars. But he was selling you a bill of goods.

    The point of impact of a shotgun is _not_ where you shoot it when you are going after a target, or pulling it off the target, or slapping the trigger or any of that jazz. It's where it places the shot when the primer fires and you are looking down the rib the way you like. And there's only one way to tell what this is and that's by shooting the gun when you have that preferred sight alignment. And the only way to get this most of time is off a rest.

    If you didn't get consistency off a rest up close, then you didn't do it enough. The first few you may pull off to one side or another, but you have your notebook with you and you are writing down every shot. Single-projectile shooters can call a shot "I pulled down" or "I threw the shot away" and you can do the same in your notebook. But by the time you have shot your way through most of a box of shells, you will have a few you've labeled"a good shot" and they are mostly in about the same place and that's the POI of your gun when you are looking down it the way you like.

    It's true that a stockfitter's results may be different from off the rest, but it doesn't make any difference, since that purposes are different.

    The bench test it to see if the gun is any good. And maybe add to your understanding a little, which is interesting and fun.

    If you want your bench-rest POI to match your shooting POI then don't just hear the stockfitter say "your gun is not positioned in your shoulder the same as if you were standing. Also your neck and cheek are not positioned on the stock the same, particularly if you have a long neck or wide shoulders. The bead and mid rib bead will be different when standing rather then sitting. " and nod your head and think "Gee, that's sounds right."

    That's what you were supposed to be doing at the bench. _Making_ the shoulder the same. Neck, cheek, face, all of that, well of course you have to make them the same. Making _sure_ the view down the rim was the same goes without saying. If you weren't willing to do that, why do it at all?

    That stuff about slapping the trigger is nonsense. If he actually told you you would get more pattern-placement consistency doing that than by a squeeze I hope you didn't believe even _that_, did you?

    So now you have two POI's. One off a bench and one freehand. They may be different. But the one off the bench is the POI. The other one should go into your notebook as well, why not? Just don't call it the point of impact.

    Neil
     
  20. phirel

    phirel TS Member

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    I agree with Neil. The POI is where the gun shoots, not where you shoot the gun.

    Irfner- You did nicely describe a method of evaluating your pattern but I still have some doubts about the POI. You stated "Then I find and mark the center of my pattern". How do you find the center? Patterning, unfortunately, is typically done in groups of 10. Do you shoot 10 patterns and get the same POI in all 10 patterns?

    Pat Ireland
     
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