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1 oz vs 1 1/18 velocities and spread

Discussion in 'Uncategorized Threads' started by John Stefanowicz, Sep 2, 2007.

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  1. John Stefanowicz

    John Stefanowicz TS Member

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    Given 19gr Green Dot in 1oz #8 vs 19 gr Green Dot in 1/8, is there #1, a difference in velocity, and more importantly, in when, or what yardage does a 12 ga with 40 constriction, develop a 30" pattern. It is a new, dedicated full choke. I have not patterned it to paper (yet). So, is a 1 oz going to open out more quickly, and because it has less velocity? Your advice please. John.
     
  2. Neil Winston

    Neil Winston Well-Known Member

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    John, translate this(below) into 1 1/8 vs 1 oz. loads and you will see that the width of a pattern is a probability, not a measurement, and so until that is determined, there is no sure answer to your question. In general, however, you can assume that the patterns will be "the same" except the lighter shot charge will be "thinner" and so, smaller from a probability standpoint.

    Neil
    Subject: ~~Pattern Question~~~
    From: Neil Winston
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    Date: 25-Aug-07 - 08:34 PM MT
    Biff, the answer is yes; even 8's (if the shell has them, see Fred above) have a "bigger" pattern than any larger size. but not because the pattern is more spread out.

    Here's what happens. Patterns are not some "size;" they just start out hot in the center and fade away as you move from the center. The consequence is that as you move from the center, the probability if a single pellet (or more if that's the way you like to think) hitting a target gets smaller and smaller.

    There are more pellets in patterns using the same weight of smaller shot, so even if everything else is constant, the probability of a hit is greater just because there are more pellets.

    What I'm after is that "pattern size" is not measured by a ruler, but rather by a probability, and the best way to do that, in my opinion, would be with Andrew Jones' 75% pattern spread if it worked for trap distances, which, unfortunately, it's not much good at.

    That may not be what you are after, but it's the best I can do.

    Neil
     
  3. Lkn4rocks

    Lkn4rocks TS Member

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    *

    John .... In all reality the 1.0 oz load is running faster than the 1 1/8 oz load with the same powder, wad, primer and hull.

    The 12 ga will open up the same pattern spread except for the density of the pattern as your question states that there is a difference of 1/8 oz of shot in the variables.

    A good rule of thumb to keep the density of the pattern the same is to go one construction tighter for 1.0 oz than 1 1/8 oz.

    I am sure you were fishing for something better than this, when you posted your thread.

    .
     
  4. Neil Winston

    Neil Winston Well-Known Member

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    Data showing that you can expect no difference in in the first part of the above-linked post, John.

    Neil
     
  5. John Stefanowicz

    John Stefanowicz TS Member

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    Given that I'm now playing with a Mod 12 with 40 constrictriction (extra full?), and going from a BT99 with its IM screw-in, what is that doing to my equation? This morning it felt like, and I did, taking it to the 22 yd, and where it was satisfying with 1 1/8 load. Yes, I realize I'm trying to account for too many variables, or am I? Advice please, and thanks for your responses so far. John
     
  6. Neil Winston

    Neil Winston Well-Known Member

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    It depends, John. If you are going from an "Invector" (short) choke, you have tightened things up a lot. If you are moving from an "Invector Plus" there probably next to no difference.

    Neil
     
  7. IM390

    IM390 Member

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    John;

    I will disagree with much of what has just been stated for the following reasons.

    1) An equivelant 1 oz load will be higher velocity because of less mass (pellets)(In reality 1 1/8 oz 19 grains is 1090fps, 1 oz should be 20 or 21 grains at 1180 fps)

    2) As such the 1 oz load will stay denser (closer to the center of the target) longer than the 1 1/8 oz load.

    3) In trap shooting a 30 inch circle is not an ideal measurement because even with a full choke it was normally measured at 40 yards. 16 yard trap is shot at 25 to 35 yards, not 40. Compare a circle at the yardage you intend to shoot for. You can always change the load to change the pattern size to fit your need.
    A modern syetem of measurement for 16 yard trap is a 25 inch circle.

    4) Find information on loading Green Dot for trap by Don Zutz. Old copies of Shotgun Sports Magazine or his book titled "Shotgun Stuff". Zutz said you could make a modified choke shoot like a full by using 19 grains of Green Dot in 1 1/8 load.

    5) Patterning your gun will be the final answer. Older Model 12 were constricted tighter because of the primitive wads that were used. Some models had short forcing cones which caused wider patterns inspite of the tight chokes. Depending on the load you may not notice anything at all from shooting a BT-99 with IM.

    6) At 22 yards there ought to be no difference in your shooting than from 16 yards. Your point of aim should be the same. The distance won't change anything until 23 yards. If you do find the M-12 a tighter pattern than what you are used to, try changing wads to a windjammer(lower pressure and wider pattern in both 1 and 1 1/8).
     
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