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7 1/2 vs. 8 (and 9) - no boredom here

Discussion in 'Uncategorized Threads' started by dmarbell, Feb 7, 2008.

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  1. dmarbell

    dmarbell Active Member

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    Because some people think that this site might become boring, I’ve decided to take the 7.5s vs. 8s debate up a notch. Let’s show just how exciting our sport can be!

    (Note: for all circular calculations, I rounded Pi to two decimal places, or 3.14.)

    The accompanying chart shows about how many pellets of each shot size should hit a trap bird at 40 yards, assuming of course a uniform pattern, which is a big assumption.

    You can see that a full face White AA Flyer, at 4 3/16 x 1 1/8, has 14.6 square inches of area. Edge on, it has something less than 4.85 sq in (because the edge on bird is not a perfect parallelogram. If anyone has this exact measurement, it would be helpful.).

    I used half the full face area as an estimate of the area seen on a quickly shot rising bird. I feel the area rises exponentially between edge on and full face, so a bird tilted about 25% toward the shooter might show 50% of the area of the full face. Not sure about this estimate, but it seems reasonable.

    You can see that for my 50% estimated area, you only have 2.8, 3.4 and 4.7 pellets per bird for 7.5s, 8s and 9s, respectively.

    I then applied the ft lbs of energy at 40 yards of 1.26, 1.02 and 0.64, respectively for the above shot sizes, to the number of pellets per bird for the three presentations.

    As you can see, there is virtually no difference between the amount of energy applied to the bird at 40 yards between 7.5s and 8s. You can also see that there is a smaller difference than many people would expect between 9s and the other shot sizes.

    The next step for me will be to pattern the gun at 40 yards with the various sizes to see which pattern better, if any. One conclusion I might be able to make is that if 9s pattern more uniformly at 40 yards, they might be a logical choice for trap.

    What do you think?

    Danny

    <a href="http://s188.photobucket.com/albums/z16/dmarbell/Trapshooters/Ballistics/?action=view&current=SizeDebate.jpg" target="_blank">[​IMG]</a>
     
  2. hmb

    hmb Well-Known Member

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    What do you have against 8 1/2s. We do not permit descriminatory practices on TS.com. The moderators are being notified and disciplinary action will be taken. HMB
     
  3. shot410ga

    shot410ga Well-Known Member

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    I have broke targets at the 27 with all three sizes, plus 8.5's. However, add some wind in any direction and I have found the 7.5's work the best. Maybe it's the weight of the 7.5's that makes them cut through the air in cross winds better. I don't know, but they work better.
     
  4. Onceabum

    Onceabum TS Member

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    Sorry...I didn't mean to snore.

    Blue
     
  5. Gary Waalkes

    Gary Waalkes Well-Known Member

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    You can break them with a .410 bore and that is only 1/2 oz of #9 shot. (But you can really load them heavy if it is windy and shoot the 8 1/2s)
     
  6. midalake

    midalake Well-Known Member

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    I hope EVERYONE uses #9...............

    GS
     
  7. Cold Iron

    Cold Iron Active Member

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    Pellet distribution you know is NOT going to be distributed down to the square inch evenly, but guess can ignore that for now. Tied into the same train of thought however you can not use a tenth of a pellet in the energy calculations. Logically it is an either\or problem. Either a full pellet hit the bird or it did not. There is no energy transfer if it did not.

    And if it did strike the bird you could start a whole new discourse on how much energy is actually transferred, what effect does it have and is anything above a certain level “wasted energy”, etc. So… exactly what effect does the energy applied have on breaking the bird? How many pellets at what energy requirement does it take to break this bird? Does a pellet with a larger surface area contribute more to the probability of breaking a bird? Well you did ask what do you think ;) Hint: I still use "heavy" aluminum arrows and never did fall for the overdraw fad.
     
  8. JBrooks

    JBrooks TS Member

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    Your energy assumptions are worthless because transfered energy will vary depending on the angle of the surface that the pellet hits, and clay targets present several angle opportunities, whether a pellet hits the oncoming or receding half of the spinning target, how close to the center or edge of the spinning target it hits and whether the target is rising into the shotstring or the shotstring is impacting the rising target from below.

    These variables of impact opportunities not only make simple mass and speed energy calculations of little value, they also make shot hardness arguments useless as they apply to target breaking ability.

    Other than that, your work is pretty ThorO.
     
  9. BustClays

    BustClays Member

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    Pellets occupy cubic inches, not square inches. The first pellet impact will alter the course of the target and make it fly into the path of other pellets in the "swarm". 2 dimensional, stop action calculations are not a true representation of what is actually happening in a dynamic 3-D environment.

    FWIW,

    bustclays
     
  10. BustClays

    BustClays Member

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    I have shot clay targets with a rifle (the targets were mounted on a target board) they do not "smash", rather they usually end up with a small hole in them. For the target to "smash", it must be rotating. So one must take into account the influence of various rotational speeds as well as apparent target size and shot/swarm density distribution.

    All in all, a very complex study which I am certain someone could duplicate with a computer generated program. However, not my forte".

    bustclays
     
  11. maclellan1911

    maclellan1911 TS Member

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    I hate 9s yuck, small dusty things, yeah yeah 7.5s
     
  12. hoggy

    hoggy TS Member

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    I find it virtually impossible to believe that 2 to 3 pellets will smoke/dust a bird. Something is definately wrong with your calculations or the reality od what is happening. 2 to 3 pellets may break a bird in 2 or 3 pieces.
     
  13. dmarbell

    dmarbell Active Member

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    Remember, these calculations are for 40 yards. Many birds are shot before that, especially by fast shooters. I don't think 2-3 pellets will dust a bird either, so maybe that's why the big dogs shoot so fast.

    Which brings up another interesting math subject. The ATA rulebook states a 42 mph launch speed. That's about 62 fps, or 20 yards per second. That means, not taking into account the deceleration for the first second of flight, that the bird is at 20 yards from the traphouse, and 36 yards from the shooter, one second after launch.

    hoggy,

    Draw a pattern the size of a clay bird on five or more pattern sheets, shoot one shell at each one from 36 yards, which the Remington Trap Guide says is about the average for singles shots, and see how many holes are in the pattern.

    Danny
     
  14. Barrelbulge(Fl)

    Barrelbulge(Fl) TS Supporters TS Supporters

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    How about 9's on a calm, clear day for teaching newbies(1'st and 2'nd time shooters), from the 16. That's what I gave my daughter to use first and second time out. Mike.
     
  15. white rattler

    white rattler Member

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    Danny, good job, but I think you have to much spare time on your hands. Why don't you come out to AZ. and break some of those targets. Trevor Dawe.
     
  16. hoggy

    hoggy TS Member

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    Danny

    Well you're thinking in 2 dimensions (pattern board is 2 dimensions)and the bird and shot is going in 3 dimentions so many more pellets than 3 is breaking the bird. 10' long shot trail by the size of the bird.

    hoggy
     
  17. dmarbell

    dmarbell Active Member

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    hoggy,

    I actually shot today with Dickgtax, and we discussed this thread. He pointed out to me that I was ignoring the shot string effect, as you stated. That's an effect that's difficult if not impossible to graph.

    However, I'd like to point out that this thread was 50% theory and 50% tongue-in-cheek. How boring can a site be with only this crap to discuss?

    Bring back the posters, and OT posts, and long live TS.com.

    Danny
     
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