Patterning

Discussion in 'Shotguns' started by PapaG, Sep 14, 2022.

  1. PapaG

    PapaG Member

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    Fun day at the range today. Buddy gave me a Mylar overlay to examine patterns. Bench the gun, shoot at 13 yards, compare POA and POI. Short on time and short on boards, I shot twelve patterns, all with the same load. Before someone complains about the range, Neil Winston, who knew more about shotguns and patterns than the whole THR membership, used that as a starting point.
    What I learned, after shooting five guns and various barrels is, a. I wish I’d never done it. B. I wish I’d done it long ago.
    Some barrels shot where I thought they did. Some didn’t.
    Two guns are going up for sale tomorrow. One is getting more use.
    Pics and details at a later date. Need to replicate parts of the test.
    Even at 13 yards, the difference among chokes is quite obvious.
     
  2. DustyGmt

    DustyGmt Member

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    I've never patterned my 30" Full remington barrel I use for trap. True story.

    I regularly shoot 23's and 24's @ 16y singles. I wonder if I actually took the time to examine my pattern with a few types of shells maybe I'd shoot even better, I'd love to spend some time patterning my Wingmaster and wonder why anybody (me) who is trying to improve their shooting wouldn't pattern their gun.

    Kind of like the guys who stick a paper plate out at 50 yards after popping an optic on their hunting rig, hitting paper and calling it good. Yeah, it's time to get to it....
     
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  3. Remington1911

    Remington1911 Member

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    I never patterned my sporting clays gun(s) as well, not quite sure why not just never bothered.
     
  4. PapaG

    PapaG Member

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    This is the first time since I started shooting my TB 47 years ago that it was fired at something other than fur, feathers or clay. I normally hold a 94% average at trap (16 and caps) with it even at my advanced age. Great pattern and location helps me understand some recent puzzling misses.
     
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  5. DukeConnor

    DukeConnor Member

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    I've never patterned my trap guns but I've been shooting them for 50 years. I thought about it last year but was afraid the results may get into my head and ruin my scores.
     
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  6. entropy

    entropy Member

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    I learned more about shotgunning in two hours of listening to Neil talk to me while he was patterning some loads than I had in the previous 20 years of shooting shotguns.

    The first thing I did after buying my Ljutic was pattern it.

    P_20200208_131912_vHDR_Auto.jpg

    The big hole is my aiming point, the wad hit down to the right. I determined it was at 70/30, which is exactly what I wanted, and I moved the comb over a little to the left, started shooting better immediately.

    Or it could help you increase them. Unless you're already 98% or more at the 27 yard line.
     
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  7. Thomasss

    Thomasss Member

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    In pattering a shotgun, POA and POI is only half the equation. Looking at a full or almost full pattern like at 30 yrds. or more will give you a better idea what the choke, load and you are doing. I looked at commercial lead field loads, my pet trap hand loads, lead pheasant loads and commercial waterfowl loads and found much interesting information on pattern density and consistency. In one case, I ended up getting a Briley imp. mod for my Urika just for trap and pheasants. Waterfowl was better using an Optima improved choke tube. And sometimes just a skeet choke over decoys.
     
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  8. kalielkslayer

    kalielkslayer Member

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    I’m a huge fan of patterning my shotguns. Last week I patterned a new 1 1/4 oz load of #6, pushed by Longshot. I patterned both the 1390 and 1440 fps loads, out of 2 barrels, total of 4 chokes.

    2 shots each, average the pellet count. But with this load I found it unnecessary, the averaging. An Imp Mod choke put 160 and 162 pellets in the 26” circle at 30 yards. An old fixed modified put 179 and 182 in that circle, interesting.

    The difference between pellet count between the 2 loads was like .3%, insignificant.

    The old fixed modified did what it always does, 70+% of the pattern above the center line. The other 3 chokes tested were more like 50/50.

    What patterning on paper doesn’t tell you is how long your shot string is with a particular load.
     
  9. PapaG

    PapaG Member

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    Over the last fifty years I've shot literally hundreds of patterns, having access to many discarded blueprints, a discarded road sign and more recently, our clubs pattern board. It was originally done to test choke work I was doing (I made sweat on chokes to turn cutoff deer barrels into turkey barrels, tuned chokes for card and turkey shoots, and tried various ways of putting choke in cylinder bore muzzle loader barrels.). It was always at 40 yards and always " throw the gun up to my shoulder, take a sight pic and shoot). Drew a lot of circles, counted a lot of holes and had a lot of success.
    Once I found out that I broke birds from the sixteen at about 34 yards, I patterned my trap guns there.
    This is the first time I ever tried the bench rest, short yardage method and realized last night that my sight picture (don't start on the "don't look at the sights" thing as after my pre routine and getting my alignment, I dont look at the sights) was different from the bench than when standing. Going to repeat using a standing rest from my trap shooting stance.
    I did run them Thursday night using my late brother's 870TC "mod trap" barrel, chosen because of Wednesdays test results.
     
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  10. Driftwood Johnson

    Driftwood Johnson Member

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    Howdy

    I did some serious patterning last year of a couple of Winchester Model 12s, my preferred Trap guns. 13 yards works because it is about 1/2 the distance that most trap targets are hit at. So it is easy to interpolate what the pattern would be out where the targets are hit, just magnify it by 2. As far as where the pattern is on the patterning board, 13 yards will still tell you if you are high, low, left, or right.
     
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  11. I6turbo

    I6turbo Member

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    I used to do a lot of shotgun patterning and load work-up. You can pretty dramatically affect shotgun patterns by playing around with wad types, shot size, shot charge, and muzzle velocity. IF your gun's POI matches the POA, you have a lot of flexibility to make a given gun perform the task at hand through load selection, even without changing chokes.

    IMO, if the POI does not match the POA, that's a problem. And a relative lot of guns don't match up very well. If you notice in some of the magazine test articles for shotguns you'll see this pretty frequently in their pattern results.
     
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  12. entropy

    entropy Member

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    Actually, the only shotgunners who really want or need POI and POA to be the same are pass shooters. Upland game hunters and clays game shooters generally want the POI to be higher than POA; this is usually expressed as a percentage of shot above and shot below the POA. For an example my Ljutic trap gun shoots 70/30, and that's with the adjustable comb all the way down. The gun was designed from the ground up specifically for trap, not adapted from a hunting gun. Some Trap shooters shoot guns with even higher POI's. You'll hear the occasional trapshooter say "my gun shoots 110/0", which is of course an impossibility, as the maximum amount of shot a shell can send is 100%.
    After 100%, POI is expressed in inches of the pattern center over the POA.
    Sporting Clays and Skeet shooters generally want the pattern about 60/40, some who shoot Trap also will use 70/30.
    Now, if the gun shoots right or left, then it's time to have a Stockfitter watch you mount the gun.
     
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  13. I6turbo

    I6turbo Member

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    If I had a dedicated trap gun I'd be good with it shooting high relative to POA. But as it is, I don't have such a gun, and I'm likely to use all of my shotguns for any and everything (various clay shooting, doves, starlings, (quail if I ever get another chance), or whatever), so I want all of them to shoot about the same, and very close to POA in terms of vertical and definitely not low. I like them to shoot POA so that I make my own hold adjustments based upon the circumstances of the shot at hand. I got used to shooting like this 50+ years ago and probably have too many rounds downrange, too much muscle memory to even think about changing at this point... :)

    If the gun shoots either left or right it's a major deal-breaker for me.
     
    Last edited: Sep 26, 2022
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  14. Virginian

    Virginian Member

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    I shot over 3,000 patterns at 40, 60, and 70 yards when I was trying to perfect long range goose loads using overbore barrels and custom choke tubes, working with Ralph Walker and Stan Baker. I was practicing at 70 yards with high speed clay pigeons and nickel and copper plated shot. I succeeded, and then they banned lead shot. I will never forgive them.
     
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  15. entropy

    entropy Member

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    You and me both! :fire:
     
  16. thu298

    thu298 Member

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    For me it is 28 yards. (16 yard line + 12 yards to the POI = 28 yards.) I get on them real quick.

    If you are interested in doing some patterning, here's a short article that might be helpful.

    If you are patterning to assess your load and choke performance, not checking for your guns Point-of-Aim/Point-of-Impact (POA/POI), here is a short list of steps to follow.

    First, you'll want to make sure you use good methods so your data will be accurate and to allow you to make fair comparisons between loads, chokes, pellets, etc. Patterning the right way does take time and effort (another reason to do it right the first time), but it is the only way to find out what a load and/or choke is doing.

    Steps for shotgun patterning:

    1) Set up a pattern board (4' x 4') frame with a backing material like cardboard or particle board to attach the pattern sheets.

    2) Get some large (40" x 40" minimum) pattern sheets of paper or cardboard. Many prefer to use 48" x 48" sheets of white paper. These large sheets will allow you to capture the majority of the pattern and make identification of the densest 30" portion much easier. This is particularly true if you are going to be patterning at distances beyond 40 yards.

    3) Measure off your shooting distance from muzzle to target. Yes, 40 yards is the industry standard for evaluating choke performance, and a good distance to pattern some loads, but you'll want to pattern your loads/chokes at the distances you'll be shooting your birds/targets. As an example, if you need a good 30 yard load/choke combo then pattern at that distance, and if you need a good 50 yard load/choke combo then you'll want to shoot your patterns at 50 yards.

    4) Now that you have a pattern board and some pattern sheets, attach a blank pattern sheet to the pattern board and fire one shot at the center of the sheet. This can be an off-hand shot or shot from a bench, it doesn't really matter, since you are just trying to get the pattern reasonably centered on the paper. You can put an aim point in the center of the paper if you need it, but you don't have to and it is only to give you an aim point. This aim point shouldn't influence you when drawing the 30" pattern circle around the densest portion of the pattern, more on this later. As a side note, you may get some indications of POA/POI issues during this pattern testing but that isn't what we are concentrating on now. It is something you may need to address latter however.

    5) Remove the sheet from the pattern board and repeat the process. Remember, you must shoot a minimum of three patterns for an average and five is better. Shotguns are not exacting instruments and variation between pattern numbers is the norm so averaging is must. And, shooting one pattern to get an idea of what it is going on with a load/choke can be misleading!

    6) Now that you have shot your patterns, draw a post-shot 30" diameter circle (use a 15" piece of string with a pencil or a yard stick with holes 15"s apart to scribe a circle) around the densest portion of the pattern. Yes, do this after the shot not before. Why after the shot? Because, you're trying to evaluate the load/choke not your ability to center a shot in a pre-drawn 30" circle!

    7) Count the pellet strikes in the 30" circle and average your pattern numbers. You can then calculate a pattern percentage by dividing the average pattern count by the in-shell pellet count if you like. To get a true pattern percentage you will need to cut open and count the pellets in several unfired shells so you will have the true average in-shell pellet count. Remember, pattern percentages tell you about load/choke efficiency, not necessarily how effective the load/choke will be at killing birds or breaking targets, see below for more details on that.

    Important points to consider:

    1) How many pellets did your load/choke put in the 30" circle? Birds of different sizes/types require different pattern densities in order to reliably hit the vital areas.

    2) What size/type of shot were you using? Birds of different types/sizes require different amounts of pellet energy to penetrate the vital areas.

    3) What yardage do you normally shoot your birds? Birds shot at longer distances will usually require larger pellets to maintain enough pellet energy to penetrate the vital areas.

    4) What yardage was your load/choke capable of maintaining killing pattern densities? Longer distances usually require tighter chokes to maintain the minimum pattern density for the birds you are after. However, larger pellet sizes (BB and larger), particularly in the hard shot types like steel, do generally tend to pattern better from chokes with less than full choke constrictions.

    5) Common sense should also tell you to pick the load/choke that gives the most consistent patterns and the one that has fairly good pellet distributed. Remember however, patterns are a random events so there will always be some variation between patterns, areas void of shot, and some clumping of shot.

    Effective patterns include:

    1) Sufficient Pattern Density -- enough pellet strikes in the 30-inch pattern to reliably hit the vital
    areas (brain, spinal cord, heart or lungs) at the distance shot.

    2) Adequate Pellet Energy -- correct pellet size and mass to retain enough per-pellet energy to penetrate the
    vital areas at the distance shot.

    3) Proper Choke -- enough choke to maintain adequate pattern density for the bird size/type at the distance
    shot.
     
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  17. entropy

    entropy Member

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    A good guide. POI/POA relationship should be established before all this happens, or it is all for naught. I do it immediately after buying a shotgun.
     
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  18. I6turbo

    I6turbo Member

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    I agree. Some pattern testing and a various bit of clay target shooting can usually tell me whether or not a new-to-me shotgun is a keeper.
     
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