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POI TEST, I NEED SOME TECNICAL INPUT

Discussion in 'Shooting Related Threads' started by WarEagle2017, Feb 14, 2009.

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  1. WarEagle2017

    WarEagle2017 Active Member

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    As soon as the weather warms up I intend to set up a test that I think will settle some issues that are often brought up here on TS>com and at ever gun club that I have been at, I have not seen this done anywhere so My intention is to do it here with the help of some of you techicnal concerned shooters,
    First let me explain the Problem ::: some shooters here think that they have to raise their POI UP when moving fron 16 yard line to the 27 yard line, and some shooters think that they have to Lower their POI from the 16 to the 27,
    Some people state that POI is POI no matter what yardage you are at ( of course staying between the 16 and the 27 )
    Many shooters get the completely lost feeling when they shoot caps and have no idea as to why they are not Hitting targets at any handicap distance.
    Well I have a theory on why there is so much confusion, I am sort of a techical nut myself and I have come up with an idea that can bring this problem to rest.
    Now first assuming that you have found a 12 Ga, load that you know shoote thru out of you trap gun we can move on from there.....
    My intention it to set My Trap gun in a good solid rest ( I am going to use a otters varmit rest ) next I am going to install a chamber mounted laser ( making sure that the chamber mounted laser is centered in the chamber by wrapping it with tape so that it fits firmly in the chamber ) then to make sure that is is comming out of the muzzle in the center I take a 20 Ga. empty and remove the primer and I install it into the muzzle of the 12 Ga. barrel also making sure that is is firmly fitted ( this will tell me that the laser is comming out of the center of the muzzle, now with all of this done so far My next step is to mount a """Quality digital calibrated""" lazer level on top od the adjustable rib, the laser that will be using will be mounted on top of the center bead and against the front bead as to create a figure 8, Now what I need from you out there is your opinion as too::: What is the average distance that a Target is broken at when shooting from the 16 yard line and what is the average distance that a target is broken at from the 27 ( need these factors ) Once that I have these distances I am going to set this experiment up and shoot the lasers thru a cheese cloth type of material to see what the intersecting points are at those given yardages, I will do this at all of my adjustable rib settinga 50-50 60-40 70-30 80-20 90-10 and 100%
    Why I am doing this is to settly My mind as to who is right or are both shooters right as to do you have to lower or raise ones POI I personally think that both methods may be right depending on what POI they have their gun set at, Before I got heavly involved in Shotgunning I used to shoot Rifle a Lot and as good rifle shooter knows ( that shoots a scope ) you bullet rises to the line of sight and then reaches what is called Mid point trajectory then later down range crosses the line of sight again ( for example a 25-06 sighted in at 50 Yards will be dead on at 50 and then about 1 1/2 High at 150 and back to dead on at 200 ( I dont need critics correcting these figures I know that they are not exact, I just tried to give some idea on what i am trying to accomplish ) I am also going to figure that a normal 1 1/8 oz load drops naturally 3 " at 40 Yards ( Come on Neil help me with this ))
     
  2. Neil Winston

    Neil Winston Well-Known Member

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    dr, I hope you won't take offense, but I've broken up your post into paragraphs and fixed a couple of typos because all in one string like that I think your readers will have too much trouble following your plan. I think it might stir more interest posted this way and I think it's an idea worth talking about here.

    dr's text, once again:

    As soon as the weather warms up I intend to set up a test that I think will settle some issues that are often brought up here on TS.com and at every gun club that I have been at, I have not seen this done anywhere so my intention is to do it here with the help of some of you technical concerned shooters.

    First let me explain the problem: some shooters here think that they have to raise their POI UP when moving from 16 yard line to the 27 yard line, and some shooters think that they have to lower their POI from the 16 to the 27. Some people state that POI is POI no matter what yardage you are at (of course staying between the 16 and the 27 ) Many shooters get the completely lost feeling when they shoot caps and have no idea as to why they are not hitting targets at any handicap distance.

    Well I have a theory on why there is so much confusion. I am sort of a technical nut myself and I have come up with an idea that can bring this problem to rest. Now first assuming that you have found a 12 Ga, load that you know shoot thru out of you trap gun we can move on from there.

    My intention is to set my trap gun in a good solid rest (I am going to use a Outers varmint rest ). Next in am going to install a chamber mounted-laser (making sure that the chamber mounted laser is centered in the chamber by wrapping it with tape so that it fits firmly in the chamber), Then to make sure that it is coming out of the muzzle in the center I take a 20 Ga. empty and remove the primer and I install it into the muzzle of the 12 Ga. barrel also making sure that is is firmly fitted (this will tell me that the laser is coming out of the center of the muzzle.

    Now with all of this done so far my next step is to mount a Quality digital calibrated laser level on top of the adjustable rib. The laser I will be using will be mounted on top of the center bead and against the front bead as to create a figure 8.

    Now what I need from you out there is your opinion as too: What is the average distance that a target is broken at when shooting from the 16 yard line and what is the average distance that a target is broken at from the 27 ( I need these factors ).

    Once I have these distances I am going to set this experiment up and shoot the lasers thru a cheese cloth type of material to see what the intersecting points are at those given yardages, I will do this at all of my adjustable rib setting: 50-50 60-40 70-30 80-20 90-10 and 100%. Why I am doing this is to settle my mind as to who is right or are both shooters right as to do you have to lower or raise ones POI. I personally think that both methods may be right depending on what POI they have their gun set at.

    Before I got heavily involved in Shotgunning I used to shoot rifle a lot and as good rifle shooter knows ( that shoots a scope ) your bullet rises to the line of sight and then reaches what is called midpoint trajectory then later down range crosses the line of sight again ( for example a 25-06 sighted in at 50 Yards will be dead on at 50 and then about 1 1/2 High at 150 and back to dead on at 200 ( I don’t need critics correcting these figures I know that they are not exact; I just tried to give some idea on what I am trying to accomplish ) I am also going to figure that a normal 1 1/8 oz load drops naturally 3 " at 40 Yards ( Come on Neil help me with this.)
     
  3. Hap MecTweaks

    Hap MecTweaks Well-Known Member

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    drhuner, you'll have fun doing everything you've outlined, it will be a chore but fun also. Keep a good notebook handy, you'll need to refer back now and then to see where things change. I won't attempt to address everything you plan but I will a couple of things.

    "Now what I need from you out there is your opinion as too: What is the average distance that a target is broken at when shooting from the 16 yard line and what is the average distance that a target is broken at from the 27 ( I need these factors )."

    Average distance a 16 yard clay is broken is around 32 yards. Some less,some more.

    Average distance a 27 yard clay is broken is around 42 yards. Some much closer, some farther. The main reason some require a higher POI from the 27 is the time difference it takes the charge to get to the longer distance.

    If you try enough different shotgun barrels with a good laser in the chamber, you'll find that not all shotgun barrels are straight and true. Your use of the deprimed 20 ga. hull will tell you this pretty quick.

    dr, since you are also a rifle shooter, you know a bullet or shot charge begins it's fall as soon as it leaves the confines of the barrel walls? I'm also fairly sure your familiar with peep-sights on a rifle and how they work? Use a deprimed 20 ga. for the muzzle end and a deprimed 12 for the chamber to create peep sights. Lock your barrel in the vice and mark a spot on the paper at 40 yards through the new set of peeps. At the same time you locate the 40 yard spot on the paper with the peeps, also mark the figure 8 spot above that one you get with the beads. This will show you the differences between the true center of the bore and the beads in where the two are different. You will need help with a partner to mark those spots at 40 yards while you align the peeps and the bead spots with a big + mark. The bottom + is the true center of your bore. The + mark above is your figure 8 bead.

    If you were to "aim" with the bore mark, the charge center will be approx. 3 inches below that mark. This is also true with a shotgun rifled slug weighing the same along with the same velocity. Using the figure 8 beads, the charge will be above the bore mark approx. 3 inches when you shoot these two marks as described. You only have know your shot charge drops from the bore 3 inches one time, don't add it in again. The same principal as with a rifle bullet but at a much shorter distance. The range at which we use shotguns, figuring the shot charge crossing line of sight compared to where it would cross again is useless.

    Hap
     
  4. alfermann66

    alfermann66 Member

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    Drhuner, I hope you have fun with your experiment. I think your tests will have slightly more value than peeing into a gale force wind. There are so many variables amongst shooters that each has to determine the proper poi for him/herself. One sets the poi where he/she breaks the most targets.

    Buz
     
  5. WarEagle2017

    WarEagle2017 Active Member

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    First of all thanks Neil that, breaking it up does make reading and understanding it much better, and i see that we are starting to get some good input.
    Let me add at this point that I do intend to use 13 yds as a starting point, one other thing that i have to get in here is ::: on Haps reply He states that a "" you know a bullet or shot charge begins it's fall as soon as it leaves the confines of the barrel "" this is True, But But !!!! this is not what I am trying to establish here, I am speaking one one laser that is in the barrel ( set to trow a level Beam _ and the other set on the rib where 50-50 POi would be the only other parallel beam,although seperated by the vertical seperation of both beams.
    My point is to establish the distance between the beams at the different distances for instance, if the distance between the beams at the muzzle is 2 " and the beams meet at 32 Yards what is the differance between the beams at 13 -32- and 42.

    To maybe put it another way to make Hap Happy LOL If I was shooting everything from a 50-50 POI gun then I would expect it to go straight out of the muzzle until gravity took control and it started to drop, what I am trying to find out is, assuming that the barrrel is level and true and the adjustable rib is raised in the back and lower in the front, it would be simular to a rifle where the shot charge is rising to a point of intersection with the line of sight which i stated above would be 32 Yards.

    Now again with all of that said, I want to establish where the shot charge woud be using the different POI settings 60-40 90-10 Unlike the rifle I am not concerned with where it crosses the level line again ( because that would be far out of the effective range od a shot shell )

    Another part of the confusion is :: Lets say the the shooter is smoking targets at 16 yards and His is shooting His gun with a 100 % POI ( He is actually Floating the target, Now using this same POI at 27 yards where lets say he should be breakinf the target at 42 yards ( give or take )His shot charhe may have dropped by gravity say 3 " But because of His High POI He is actually still shooting way over the Target Bucause at some point out there the target starts to drop and then there is no longer a need to have a gradually rising shot string.

    So now another factor I need to make this experment workis ::: At what point on a calm Day ( No wind ) I am talking distance here does the target start to drop ???? Opinions please
     
  6. WarEagle2017

    WarEagle2017 Active Member

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    Alferman I know that this is true but for the one out there that have that LOST FEELING every once in a while I think it may help, I intend to make up some drawings on this with the Hope that it can help someone if only for Me, I have been puzzled with this for a while now...
     
  7. phirel

    phirel TS Member

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    drhuner You asked "if the distance between the beams at the muzzle is 2 " and the beams meet at 32 Yards what is the difference between the beams at 13 -32- and 42." The answers are 13 yds-0.8125 inches;, at 32 yards- 2 inches: at 42 yards- 2.625 inches. If you are interested at all, at 36.8459 yards the beam would be 2.3028687 inches high.

    The two straight lines would diverge linearly at 0.0625 inches per yard.

    Pat Ireland
     
  8. WarEagle2017

    WarEagle2017 Active Member

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    Pat No Pun intended but your caculations cannot be correct, read you post again, First I stated that if the beams were 2" apart at the muzzle and they MET at 32 yards, you post says that they are 2 " low at 32 yards, it seems like you missed the part where i said that they intersect at 32 yards, so from that point on they should be on the Plus side of the equasion
     
  9. Hap MecTweaks

    Hap MecTweaks Well-Known Member

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    dr, whether it be a shot charge or a slug,bullet, whatever, once it leaves the barrel, it begins to fall. With your shotgun, your in essence dropping or lobbing the charge onto the 40 yard mark.

    I merely pointed out the centerline of the bore is where the initial drop comes from with a shotgun charge. Most shotgun barrels are "regulated" at 40 yards, some are n some ain't! The factories have already accounted for that 3 inches of drop IF, the barrel was regulated properly.

    Neither a shot charge nor will a bullet will rise above the centerline of the bore, according to Mr.Newton or one of those guys? The rib and bead on top of the barrel takes this into account when it's set up properly.

    I just pointed out another test you can try while your having fun with the 3 inch drop stuff.

    Using terms like "floating" at 16s and the same at the 27 isn't very accurate in terms of writing down specific numbers in your notebook either as you'll find. Have fun!

    Hap pynow :)
     
  10. WarEagle2017

    WarEagle2017 Active Member

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    Hap Harry i do appreciate your input but you are missing the point, I am fully aware that the shot charge just like a bullet starts dropping when it leaves the barrel, but when one ( One meaning Me ) it talking about the projectiles travel, in relation to the line of sight is a completly different matter, If I was looking out of the barrel ( thru the barrel hole ) I would agree with you but I am not I am looking down an incline plane, on the top of the barrel and the projectile has to cross this line of sight although the projectile is not rising to the line the line is lowering itself to the dropping line of the projectile and at that point is crossing over the projectiles line and rising above it, you must understand I am not saying that the projectile is rising is actuallity but it is rising to the line of sight, I have a program that I will load and try to get a pic of it here to explain it better. But keep giving me Hell I love it... LOL
     
  11. phirel

    phirel TS Member

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    drhune- Yes, I had the beams at 0 leaving the gun and 2 inches high at 32 yards. So the beams would decrease at the rate of 0.0625 inches per yard from the end of the gun to 32 yards, and then diverge at the same rate after 32 yards. If you will allow, I would change my answers to: At 13 yards, the beams would be 2-(.0625 X 13)= 1.1875 inches--- at 32 yards they would meet--- at 42 yards they would be 10 X .0625 = .625 inches apart. And, at 36.8459 yards they would be 4.8459 X .0625 = 0.3028687 inches apart.

    I calculated the rate at which the two lines diverge the first time, I just started at the wrong point and omitted the convergence that took place before the divergence.

    Pat Ireland
     
  12. WarEagle2017

    WarEagle2017 Active Member

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    Ok Pat dont let it happen again,,,, LOL Just Kidding Very good info, Thanks
     
  13. WarEagle2017

    WarEagle2017 Active Member

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    This pic is for Hap, It is not the actual trajectory of a 1 1/8 os shot charge I am just trying to show Hap what I mean about the projectile rising to the line of sight......Line of sight is the broken line and the solid line is the path of the Bullet.
    <a href="http://s108.photobucket.com/albums/n37/drhuner/?action=view¤t=forhap.jpg" target="_blank">[​IMG]</a>
     
  14. Hap MecTweaks

    Hap MecTweaks Well-Known Member

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    dr, I didn't miss anything your attempting to try. I say this because I have already used a laser both in the chamber and muzzle end for checking out a barrel. I haven't used them as you plan though and I wish you success in your tests. Where and what was said that made you feel as though I was giving you hell? I really wasn't or didn't intend it to sound as if I was.

    Keep good notes while having fun, lots of questions may be asked after your tests. Hap py
     
  15. WarEagle2017

    WarEagle2017 Active Member

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    No Hap I ment no ILL feelings at all, I just used the term Hell as a means to keep My interest in the subject, and i appreciate all of the inteligent opinions on the subject your included, but believe me the discussion about the bullet raising up to the line of sight has recieved a lot of comments just like yours until i explained it clearly, like I said before we all ( or most ) know that the bullet starts to drop as soon as it leaves the barrel and sometimes it is hard to explain to someone that although it does do this it has to rise to the line of sight, being that the sights are mounted on top of the firearm,,, I guess it might be better to say that the line of sight angels down to the path of the dropping bullet, if one wants to look at it that way, 6 of one and 1/2 dozen of the other. LOL
     
  16. hmb

    hmb Well-Known Member

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    dr,

    Another example to illustrate your point would be a 30 caliber target rifle with iron sights sighted in to hit the center of a target at 25 yards will also hit the center of a target at 200 yards with the same sight setting. HMB
     
  17. WarEagle2017

    WarEagle2017 Active Member

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    HMB ASK YOU YOU SHALL RECIEVE, I did this quick using a 150 Grain bullet so it passes at 33 and 200 Dead on..<a href="http://s108.photobucket.com/albums/n37/drhuner/?action=view¤t=Hmb.jpg" target="_blank">[​IMG]</a>
     
  18. WarEagle2017

    WarEagle2017 Active Member

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    Also anyone wanting some more tec stuff go to this site :
    http://www.shotgunsportsmagazine.com/downloads/shotgun_statistics.pdf
     
  19. WarEagle2017

    WarEagle2017 Active Member

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  20. WarEagle2017

    WarEagle2017 Active Member

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    Here is a more descriptive pic of the rise of the Bulley
    <a href="http://s108.photobucket.com/albums/n37/drhuner/?action=view&current=Encore.jpg" target="_blank">[​IMG]</a>
     
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