Myth-Busting: 1″ per Yard Shotgun Pattern Spreads

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Grandpa used to tell me that buckshot spreads 1″ for every yard from gun. I took him for his word, but suspected he was wrong after patterning my 870 and 930 shotguns. I chalked my results up to long barrels and modern technology, never putting the assertion to a comprehensive test.

RifleShooter, however, was not content with the same assumptions. Instead, they comprehensively tested patterns with 18″ barrels and various chokes, including a back-bored barrel almost the the muzzle. Most stock barrels were less than .5″ per yard. Only the back-bored barrel was close to the 1″ claim, coming in at .96″ per yard.

The patterns at 20 yards. Click on the picture to be taken to the Rifleshooter article.

The patterns at 20 yards. Click on the picture to be taken to the Rifleshooter article.

The results chart is telling:

Barrel 7 yards 15 yards 20 yards Avg spread per yard
Back Bored 2 5 ¼ 7 .35”
Vang Comp 1 ¾ 7 7 ¼ .36”
Remington IC 5 10 7/8 11 ½ .58”
Remington Cyl 3 ¼ 9 1/8 12 .60”
Back bored 2” from muzzle 4 ¼ 15 ¾ 19 ¼ .96”

 

Hit the link for the full article, pictures, and analysis, including the tutorial on back-boring. 

Two morals to this story:

  1. Aim
  2. Pattern your shotgun

Nathan S.

TFB’s newest resident Jarhead, Nathan is currently working in the Defense industry in international sales. A consecutive Marine rifle and pistol expert, he enjoys local 3-gun, bull-pups, and high-speed gear. Nathan has traveled to over 30 countries in the last three years working with US DoD & foreign MoDs. You will likely find him either in an international airport or on the local range in NE Indiana.

Nathan can be reached at [email protected]


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  • JumpIf NotZero

    Federal Tactical / Flight Control. Done.

    I know my all of my shotguns will pattern in a first at 25y regardless of barrel, forcing cone, or choke. It’s really the only buckshot I’ll put in my guns.

  • allannon

    Granddad was probably using paper shells with a crappy wad, and quite possibly home-cast shot. That might have a significant effect on spread over a modern round.

  • dan citizen

    Great article. It’s pretty load dependent too. Out of many shotguns/loads my best combo was a winchester 1300 and s&B OO buck. It would hold a nice even group.

  • Mystick

    I would think it would depend largely on the choke employed.

  • gunsandrockets

    Interesting test, but flawed. It looks like groups measured were based upon a single shot per target. If at least 5 shots (better yet 10) per target were measured for group size I would find the conclusions of the test more credible.

  • Duray

    You said “I chalked my results up to long barrels…” Please don’t keep spreading the myth that pattern spread is a function of barrel length.

    • Michael Bergeron

      Your spread is a product of velocity, choke and round construction, if you have a longer barrel you have more velocity(for a given powder charge) and less spread same with a tighter choke and a better wad and packing of pellets.

  • El Duderino

    Someone tell game designers, quick! They all seem to think it’s 1′ per yard.

    • wojtekimbier

      They all seem to think it’s 3″ per yard actually :)

      • gunslinger

        and full dmg at 1″ to 100′

  • Guest

    Not to nitpick, but you did have me in mythbusters mode when I started reading the article. Since paper targets don’t (as far as I know) affect ballistic performance that much couldn’t they have used multiple targets in a line for each shot to get a clearer picture of the spread pattern? A target every 5 yards would, I’d think, give cleaner results about the spread pattern. I know that you can generally count on bullets traveling in fairly predictable paths, but I’d imagine that imperfect spheres without rifling have weirder flight paths.

  • SafeArmsReview

    This “1” per yard” is a rule of thumb and as you know some thumbs are bigger than others.

    ;)

  • Geodkyt

    From the article: “We selected this full power, 1325 fps, 2 3/4″ load because we have found that the tactical and reduced recoil loads on the market pattern tighter then non premium buck. . . ”

    So, they selected a load that is specifically designed to open it’s pattern slower than traditional ammo, and are surprised to find out it opens slower than Grandad (who was using traditional ammo with “old fashioned” wads, not wads with VERY sophisticated modeling involved in their design? Shocking.

    Meanwhile, my cylinder bore Mossberg 500, using “non-premium” buckshot (S&B #4 buckshot) and El Cheapo Winchester “party pack” (#7 or #8 birdshot) patterns almost EXACTLY 1″ per yard (at least to 11 yards – the maximum distance available in my house, so the max I patterned to). But then, I’m using ammo that is pretty much the same as “Grandad” had available to him. Not far more expensive premium shells.

    • gunsandrockets

      To be fair to the article, I think you are misreading what you quoted. Admittedly that quote could have been better written, and I almost made the same error you did. But if you read it carefully you can see they used ammo which they believe to make a larger group pattern.

      • Geodkyt

        How does “patterns tighter” equate to “patterns less tight”?

        And isn’t one of teh major selling points of those tactical and reduced recoil loads that they PATTERN TIGHTER than “traditional” buck? I mean, that’s how they are advertised, after all. . .

        • gunsandrockets

          I’ll spell it out, the test ammo they chose is not ‘tactical’ and not ‘reduced recoil’. The sentence is just poorly constructed. The intention of the sentence is to CONTRAST their test load with premium tactical and low recoil buckshot loads.

          “We selected [THIS FULL POWER LOAD] because we have found that the tactical and reduced recoil loads on the market pattern tighter then [NON PREMIUM BUCK]. . . “

  • cawpin

    I’m not really sure why this is surprising. That 1″ per yard rule was fairly accurate until modern wad design changed it. That is the main reason patterns are tighter now.

  • Dean Seaman

    allannon makes a good point. That’s a very old saying. The article would’ve held up better had the testing initially been performed with “vintage-style” ammo in “vintage-style” weapons. Remember, at one time, a shotgun was either “choked” or not. I suspect the saying alludes to non-choked shotguns (what we would call “Cylinder Bore” these days). Could be the difference between self-contained cartridges and black powder muzzle loader guns, too. Do the testing and comment on the result in that fashion (thus, in context with the old saying), THEN perform similar tests using modern weapons and ammo to show how out-of-date that saying is.That is how I feel this article should’ve been handled. All I got out of this particular article is that the writer/tester didn’t see a big enough picture from the get-go.