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Does shot size effect pattern diameter?

Discussion in 'Uncategorized Threads' started by Border Bandit, Nov 5, 2008.

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  1. Border Bandit

    Border Bandit Well-Known Member

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    Simply, will two given loads using the exact same components and fired from the same gun/choke combination, at the same distance and weather conditions, at 12 noon, on Saturday, but differing in shot size, produce the same diameter pattern?

    Example: Once fired Remington STS hulls, using Remington primers, loaded with 17.5gr Hodgen Clays and Remington Fig 8S wads, using West Coast Magnum #7 1/2 shot or West Coast Magnum #8 shot, loaded on the same press, produce a different or same pattern DIAMETER?

    If they do, what is the rational for using #8 shot for singles and switching to 7 1/2 for Handicap? I mean, if the pattern diameter IS the same, and #7 1/2 pattern DENSITY is sufficient to break a target from the 27yd line, what is the rational for using #8 shot at closer distances? Wouldn't it logically follow that using 7 1/2 shot for both singles and handicap make sense?
     
  2. zzt

    zzt Well-Known Member

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    Mike, I use West Coast Magnum shot exclusively. In my experience both 7 1/2s and 8s will give you the same size pattern. Naturally, 8s will give you a denser pattern. That being said, my last unsingle barrel threw tighter patterns with 8 that with 7 1/2 with the identical load. It was an anomaly.

    The rational for using 7.5s for longer distances is you don't believe 8s carry enough retained energy to do the job. If you do believe that, as I do, you would be insane to give up the denser patterns you get with 8s.
     
  3. Dr.Longshot

    Dr.Longshot Banned Banned

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    The bigger the shot the tighter the pattern, in a non altered Bbl.

    Load #8s and then use same load w/ 6s and compare patterns.



    gary Bryant
    Dr.longshot
     
  4. phirel

    phirel TS Member

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    zzt- You and Neil have furnish me a lot of good technical data on this question and I am trying to reconcile this information with my non technical observations. When talking with shooters whom I respect, and every other poster on this site should respect, I find they nearly uniformly use 7.5 shot from the 27. These are shooters who have made the All American team at least five times (Leo H., Phil K., Kay O., etc.). I have also several times looked at large samples of new hulls ejected from shooters on the 27 yard line. These almost always 7.5 shot shells.

    I just can't decide it the additional 20 ft/sec greater retained velocity of 7.5 over 8 is important. Both sizes retain enough energy to break targets with some energy to spare. Greater wind deflection of the smaller shot could be a factor of some importance as could the affect air density on smaller shot.

    Just for fun, last Sunday I mixed a box of my handicap reloads. Fifteen shells contained 7.5 shot (as printed on the bag) and ten were #8 shot. I did not know the size of the shot in the shell I was shooting. I could not tell any difference. Of course, this very limited test really means nothing, but my confidence in my reloads means a lot. I could shoot the very best shells and if I don't believe they are the best, I would not shoot well.

    Pat Ireland
     
  5. birdbuster

    birdbuster TS Member

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    I know people that use 8 1/2 1oz. at 16 yds and run 100s and 8s at 27. This is also temperature dependent. I would suggest using a pattern board to check this out. The speed at 27yds is the unknown, and could be used with the varying weight of different sizes the pellets to determine the 'energy' in each bb size. This would help answer our questions.
     
  6. Jawhawker

    Jawhawker TS Member

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    Smaller the size of shot the more that wind resistance will effect and cause a somewhat larger pattern only to a minute degree. It would hardly be noticeable for 16 yard distances. Also there are more pellets with smaller pellets thus the chance for more to deform which would also on paper appear to present a larger pattern diameter.
     
  7. Texas Ton

    Texas Ton TS Member

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    """"""Wouldn't it logically follow that using 7 1/2 shot for both singles and handicap make sense?"""""""

    Illogically, I use 8's from the 16 when I want to just leave a hanging ball of powder, 7 1/2's will do the same thing when centered exactly------I'm not always exact ;^)

    I shoot 7 1/2's from that point back, regardless. Anyone ever been hand loading targets in the house and listened to shot ringing off the target, but it didn't break?? And know who was shooting, either by their calls or you knew who was first in the squad and actually studied as best you can, to breaks from there??

    Not scientific enough for you??

    Is for me, and I've heard and watched lots of shooters that ""rang"" targets with 8's and broke them every time with 7 1/2's. More especially if you're shooting 27 yard doubles, and on the second target. There's enough energy difference there for me to stay with 7 1/2's then and I'm not opposed to using them from the 16.

    To the original posters question, I've shot 100's of patterns and at least through my guns, the pattern width "may appear" slightly larger with smaller shot, but only because of the increased pellet count. You might have 1.5 #9 pellets to every 7 1/2 pellet, in the outer band, or outside that band.

    Another old wives tale, as far as I'm concerned.
     
  8. otnot

    otnot Active Member

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    A couple of years ago I wanted to know what the answer to this question was so I took layers of cardboard and taped them together and shot 7.5 at one target and 8's at the other at 55 yards. I was surprised that the 7.5 didn't penetrate much more than the 8.5 and the pattern would have scared you. I think a phone book shot at 50 yards would give you better results if you could hit it with a pellet or two.
     
  9. birdbuster

    birdbuster TS Member

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    I just like using 7.5 for everything so I don't get my shot in my reloader mixed up!
     
  10. zzt

    zzt Well-Known Member

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    Maybe this will help some of you decide. Shotgun Ballistics for Windows includes a program called Shotstring Effects. It is a mathematical and graphical representation of a crossing target's flight through the shot string (maximizes the number of potential pellet hits).

    Setting it up for a 40 yard shot at a 6 square inch target crossing at 30 fps, using a full choke and considering only the central 30" diameter of the pattern shows the following. For a 1 1/8oz load of 8s launched at 1200fps, only 60 pellets have any chance of hitting the target. Changing to 7 1/2 shot reduces the potential number of hits to 51. That is a 15 percent reduction.

    The sure kill area of a pattern is the area that guarantees at least a one pellet hit on the target. Naturally, the assumption is that pellet has enough retained energy to break the target. Now, if you are Dead Eye Dick and perfectly center every 27 yard handicap target, you have nothing to worry about. If you are a little less than perfect and miss centering by no more than 1.1" you also have nothing to worry about. If you are not that good, every increase in sure kill area helps your chances. Moving from 7 1/2s to 8s, still assuming 80% PEs at target distance, you can be as much as 4.8" off center and still be assured of a hit. So you sure kill area has been increased by 434%. I'd say that is pretty significant.

    Any way you slice and dice it, you chances of breaking a 27 yard handicap target are maximized by throwing 1 1/8oz of shot into the densest pattern you can get using the smallest shot size retaining enough energy to break the target. That's a fact. The rest is up to you. If your brain tells you you have to use 7 1/2s, do it. Remember, placebos do sometimes work when the patient believes they are getting a dose of really effective medicine. Me, I want the real thing.
     
  11. Neil Winston

    Neil Winston Well-Known Member

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    Mike, the problem is there's no such thing as pattern diameter. They fade, non-uniformly, from lots of pellets to hardly any at all so any setting of a particular number will be arbitrary.

    Shotgun-insight calculates (that is, does not count) a figure called 75% diameter which is shorthand for "the diameter if a theoretical pattern which would enclose 75% of the pellets on this paper."

    One of the problems using it for trap patterns is that all pellets aren't on the paper and that introduces variability which probably would be far less if we could count all the pellets.

    I'm doing this from memory since I'm at the Autumn Grand, but I don't think there was much difference when I did 10 patterns of each - 8's and 7 1/2's - and compared that statistic. (If, when I get home, I find that's wrong, I'll correct it.) But that doesn't quite tell the whole story, since once the programs calculates the 75% diameter of say 26 inches there are still more 8's outside that than 7 1/2's and so is the diameter bigger with 8's even though the number is the same?

    I've found the pattern percentages for each to be about the same as well. Mike, I think all in all, you'll find the patterns from each about like the other, except the 8's are denser overall, everywhere.

    Few will believe it, but I get about the same insensitivity to shot size carried over to charge weight (1 1/8 vs 1 oz vs 7/8).

    None of this should come as a surprise. Nature is analog, not digital, that is continuous, not discrete. Sure 7 1/2's are bigger, but not all that much. In your example, Mike, everything else is kept the same and you list a lot of things which could (potentially) affect pattern. So if you change just one of many determinants of pattern and then not by much, you shouldn't expect "new rules" to suddenly apply, should you?

    And Pat, I think my answer to you is similar. I, for example, would never put a specific number to the energy required to break a target. Surely it's a continuous variable.

    In testing a drug, you are trying to find the ED/50, that is, a dose which proves to produce an effect in 50% of the tested population. Some patients will be very sensitive and need less; others will never show an effect at all.

    I'm betting pellets and targets are no different, some breaking with a lightly energized pellet, some resisting even a bigger faster one. I also think that if it works for Kay, it would work for me if I shot as well (and quickly) as he does, and that goes for all those you named as well, of course.

    I think I can kid myself in looking at a break from one of the 3/7 1/2 Gold Medal Papers I favor that it wouldn't have been as "hard" with 8's, but I doubt I could pass a test on that no matter how many times I took it. Me? I'll go with 7 1/2's with lots of pellets, smaller shot with fewer pellets. Why should I use anything different from the people who are beating me?

    Neil
     
  12. Dr A C Jones

    Dr A C Jones Member

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    My best estimate is that #7.5s will on average deliver a pattern ~1.6% tighter than #8s (in terms of PE at 40 yards with a full choke this equates to about 1% difference), i.e. a very small amount. This is much less than the average pattern to pattern variation. To resolve to a reasonable level of confidence such a small underlying difference between #7.5s and #8 would need results from ~70 patterns of each, i.e. 140 in all. The practical conclusion is that the average pattern diameters are "near enough the same", but the effect of the extra pellets of the #8s gives a denser pattern which in turn gives a wider effective pattern.

    Andrew.
     
  13. Neil Winston

    Neil Winston Well-Known Member

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    I'm back home, let's see what I have here on my home computer . . .

    But first a disclaimer, suggested on another thread by Buzzgun, These results apply to this test, with this gun, these shells. They are descriptive statistics and sometimes quote low-number differences of a percent here, a fraction of an inch there. They do not claim that these differences are significant or "mean" anything at all. Were I to try to extend these data further, to statistically-significant levels, I'd need many times the number of patterns I shot and the results might the other way, just as Dr. Jones advises. Still, I think most who did something like I've done would get results about like what I got.

    1. Let's start here, organizing the patterns from least to greatest pattern efficiency (PE) , that is, pattern percentage in 30 inches.

    [​IMG]

    2. But if you were just looking at patterns and not counting them, could you guess what was going on? Here are the same data, organized the same way, but without the overall structure visible, that is the 30-inch PE

    [​IMG]

    Well, clearly, you can't tell anything at all. But note too, how much variability there is, pattern-to-pattern. There are no certainties here, no sure-hit areas all the time, just a lot of "most-of-the-times."

    3. If I was careless about significance, I could cite this as one of these "counter-examples" - proof that _my_ Bowen has some supernatural power to resist nature;

    [​IMG]

    . . . but look at the difference, small, and the range of values, large, and see that getting such a result has a probability of almost 50% when there is really no difference at all.

    4. Still, more 8's is more 8's, percentages aside:

    [​IMG]

    5. And last, the graph Mike Poore wondered if existed; it's about time to answer the one question that started all this:

    [​IMG]

    Should we take that half-inch seriously? Not with variability like this over a range of three or four inches. The answer to MIke's question is that the best bet is there is no difference in pattern size between 7 1/2's and 8's when all the things he mentions are controlled for.

    Neil
     
  14. racer

    racer TS Member

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    Mr. Winston- I would like to have a private discussion about shot patterns but I'm not sure how the "PM" system works, any help? Dan Ehlers 9914542- WI
     
  15. Neil Winston

    Neil Winston Well-Known Member

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    Why not just call me, Dan? I'm home a lot in weather like this. 651-645-8443.

    Neil
     
  16. racer

    racer TS Member

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    Neil- looking for my phone right now- Dan
     
  17. Border Bandit

    Border Bandit Well-Known Member

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    Neil and others, thank your for your thoughtful and thorough response(s).

    I just came back from CAC at Ebensburg, PA, where I bought my shot for next season; all #7 1/2's, which, by the way, was priced, @ $28.20 for a 25lb bag of West Coast Magnum.

    The #8's I have on hand will be used for 1oz sporting clay loads, as will the remaining Clay Dot powder.

    The new loads will be: Remington STS hulls, Remington primers, Green Dot powder, Downrange Windjammer wads, and 1 1/8oz #7 1/2 Magnum shot @ ~1,200fps.

    I believe that Clays & Clay Dot with resultant higher pressure required to obtain 1 1/8oz handicap loads/velocities were responsible for the scorched hulls and melted wad residue. Interestingly, when loading 7/8oz & 1oz loads with these powders for clays, the residue and hull discoloration turns from black to grey.

    Thanks again, everyone, for a thoroughly enjoyable and informative discussion .....mike
     
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