Maximum Effective Range of Buckshot

Saturday, April 28th, 2018

Watching an old police-training film, Shotgun or Sidearm?, raised some questions about shotgun patterns, and commenter ASM826, who co-blogs with Borepatch, emphasized the importance of modern pattern-controlled shells.

Brass Fetcher Ballistics tested 12 gauge shotshells — using #4, #1 and 00 buckshot (both plated and unplated) — to determine the maximum effective range of each type of shotshell when shot through a practical 12 gauge shotgun with cylinder choke.

Maximum effective range is defined here as:

  1. Having a hit probability greater than chance (greater than 50% of pellets make scoreable hits on target).
  2. Buckshot traveling fast enough to make incapacitating hit at this range (12.0” or deeper penetration in nominal 10% ballistic gelatin).

They immediately found that unplated #4 buckshot won’t reliably penetrate 12 inches of ballistic gelatin, so it is not acceptable for self-defense at any range. Plated #4 buckshot only penetrates 12 inches of ballistic gelatin out to 11 yards, so it’s not much better.

Bucketshot Velocity vs. Distance
Buckshot Velocity and Penetration
Unplated #1 buckshot penetrates 12 inches of ballistic gelatin out to 29 yards, while plated #1 is effective out to 51 yards.

At this distance, keeping most of the pellets on the target becomes an issue, as they found in their testing:

Distances between muzzle and target for the #4 buckshot and unplated #1 buckshot correspond to the maximum distance at which a single shot pellet is expected to be traveling fast enough to score an incapacitating hit. The remaining shotshells were shot at 40 yards distance.

Buckshot Hit Percentage
Buckshot Maximum Effective Range

It will be noted from above that the physical distance between the muzzle of the test shotgun and the paper targets was 40 yards for the #1 buckshot (plated, pattern-controlled), 00 buckshot (unplated, buffered) and 00 buckshot (plated, pattern-controlled.) This was to ensure that all shot pellets struck the paper and could be accounted for in the further range calculation. The 00 buckshot (unplated, buffered) load impacted the targets with greater than 50% of the shot pellets at least 50% of the time. The #1 buckshot (plated, pattern-controlled) load had a higher hit probability than the unplated 00 buckshot (maintaining a hit probability of 50+% out to 57 yards) but the individual pellets lacked the mass and initial velocity to retain terminal effectiveness beyond 51 yards. As such, the maximum effective range of this load was determined to be 51 yards. The 00 buckshot (plated, pattern-controlled) load maintains a hit probability of 50+% out to 52 yards, which is the limiting factor in maximum effective range because the individual pellets are sufficiently massive and have a high enough velocity to retain terminal effectiveness to a distance of 104 yards.

Determination of hit probability (past the 40 yard distance that was physically tested at) was based upon the average mean radius of the tested 10 shotshell/10 target test groups. Mean radius is defined as the average of the straight line distances between the Center-of-Shot-Group and each shot (USARIEM TECHNICAL NOTE TN-01/2 STATISTICAL MEASURES OF MARKSMANSHIP Richard F. Johnson Military Performance Division February 2001 U.S. Army Research Institute of Environmental Medicine) and was determined by utilizing OnTarget TDS software (OnTarget TDS).

Summary:

If your duties or circumstances lead you to carry a shotgun for self-defense when outdoors, we encourage you to make use of shotshells utilizing a pattern-controlled shotcup and copper-plated shot pellets. As tested, pattern-controlled #1 buckshot presents an interesting alternative to the more traditional 00 buckshot (also pattern-controlled) in that the maximum effective range is the same but the felt recoil is reduced by 23% over the 00 buckshot load. Since there is no difference in the long range performance of the two shells, we recommend the Federal LE132 1B load to maximize range and minimize recoil for the defensive shotgun. For self-defense indoors or in environments that physically cannot exceed 10 yards distance, we recommend #4 plated buckshot at 1250 ft/sec or higher muzzle velocity. You can maximize your shotguns effectiveness by selecting buckshot that is effective out to your maximum planned engagement distance and no further.

Comments

  1. Bob Sykes says:

    At ranges like 50 yards, I should think people would use slugs to incapacitate someone. Some states, like Ohio, require deer hunters to use slug guns, and not rifles, because they are so built up.

    Anyway, the arguments re incapacitation based on gelatin leave something to be desired. In a study of some 2,000 to 3,000 actual handgun shooting incidents, it was shown that if deterrence were the criterion (rather than incapacitance) then just about any caliber handgun sufficed, even the .22 LR. Of course, shooting someone with a .22 LR only injures him, but the severity of the pain in most instances drove the attacker away.

    Some states have a “stand your ground” law, but most do not. In most states, shooting someone in self-defense is likely to get you prosecuted. In those states, any use of a gun is regarded as illegitimate. In those states, I would rather injure someone, even a home invader, rather than kill him.

  2. Where did the 12″ requirement come from? I once did a multiple regression on the Marshall and Sanow data, and found that penetration (in gelatin) beyond ~ 12″ was entirely wasted, as one might expect given the depth of a torso. Even if all the kinetic energy is dumped in the first 3″, the fact that this would require explosive expansion and energy dumping means the round is effectively using its KE. The idea that a bullet in the side might be stopped “harmlessly” in an arm has even less applicability to multiple projectile shotgun rounds.

  3. Kirk says:

    It’s been years since I read about it, but I think that the 12″ penetration requirement basically results from practitioners going “…well, that sounds about right…”.

    Just like most of this arena, the science is piss-poor. And, the reasons for that stem from the reluctance to actually do the necessary in order to get the data… You want to know how well the M855 works in Somalis? Well, asking the Rangers who were shooting at them with that cartridge out of the M4 and M16A2 is really just this side of useless, as the purely subjective data that you’re going to get will be filtered through their perceptions, the stress of combat, and a host of other extraneous factors like, was the guy doing the shooting actually hitting his targets…?

    You want to know how all this stuff actually works, you have to get the raw numbers: What is the round doing downrange, what does it have to get through, and what are the actual realities of the situations we’re using them in. In a lot of very profound ways, we really don’t know.

    Take the way they tested the XM-25: Sent the shiny new toy to Afghanistan, had a few units carry it around and fire it into the general direction of the enemy who shot at them, and magically assume that there was a connection between the firing of the XM-25 and the enemy ceasing fire. I can think of a dozen different reasons why they might have done that, and just about all of them don’t tell us diddly-squat about the efficacy of the XM-25 as a weapon. You want to know how well it works? Well, you need to connect it with some bodies, then–That’s the only thing that will tell you the reality. And, nobody wants to do that, whinging about it being “…too hard…”. Well, sure… But, how else do you propose to determine how well a weapon works, other than by examining its effect on the enemy?

    There’s a lot of this crap that just isn’t that well-reasoned; OK, we have few cases where the casualties coming back into the aid stations have bayonet wounds. What does that mean? We can make the assumption that the bayonet sees little use, or perhaps, just perhaps, we might infer that the wounds delivered during a bayonet charge are more likely to be fatal, and that most of that weapons victims never made it back to the aid station… The only way to really tell would be to have the folks doing Graves Registration do some form of survey on the casualties they collect and bury, to attempt to determine what killed them, and then gather the statistics. Given the error rate in civilian forensics when it comes to determining cause of death, I don’t hold out a lot of hope for the quality of that data, either…

    In my opinion, what really goes on during a firefight in combat is on the other side of a veil we don’t wish to see through, or we would go to some effort to pierce it. Why this is, I cannot say, but I can say that most of what people discuss as facts in this sort of affair are generally the product of subjective delusion.

  4. Wang Wei Lin says:

    I view self defense like a car. If a car loses its fluids it will stop or die. Sig Mosquito .22, SA XD 9mm or Mossberg short 12 gauge, if I poke enough holes in you you’ll stop. Pain aside, you can only last so long full of holes.

  5. Isegoria says:

    The guideline that a bullet needs 12 inches of penetration goes back to the Dade County Shootout, the most studied gunfight of the 20th Century:

    Early in the fight, a bullet from Dove’s 9mm pistol pierced the opposing rifleman’s arm and into his chest, slicing an artery and inflicting a “fatal, but not immediately neutralizing” hit when it stopped short of his heart. It was after that, that he inflicted most of the deadly damage. FBI subsequently adopted a standard requirement that their handgun ammo penetrate a minimum of 12” into muscle tissue-simulating ballistic gelatin, a standard most law enforcement and many lawfully armed citizens subsequently adopted.

  6. Kirk says:

    @Isegoria–Partially true. The 12″ standard was running around in ballistics circles for years, though. And, stemming from… What, precisely?

    To my knowledge, nobody out there had or has actually done the work to really definitively and qualitatively validate this number. The fact that it’s a nice, round number that “sounds about right” ought to draw your immediate suspicion–We very rarely run into situations where there is actual work done, and the number work out so neatly rounded off.

    I like 12 inches, but I also am suspicious of anything that “just sounds right”. Sometimes it is, sometimes it isn’t.

    Dr. Martin Fackler is the seminal source in a lot of this stuff, and he’s the guy who started talking about this off-the-cuff back in 1988, after the FBI shootout you refer to. Unfortunately, everyone assumes that his word was holy writ, and that the statements he made in an impromptu setting were actually “scientifically validated”, when they weren’t really.

    Stop and think about it: For most subjects, in most situations, you’re good with 12″ penetration. You’ll get CNS shutdown, hitting in the right place, or you’ll do enough damage to the cardiovascular system to attain similar results. However, that’s assuming an average target, standing, whose head or thoracic area is presenting itself. Should conditions differ, in either target or presentation? 12″ probably won’t be enough.

    It’s like hunting; you go after elephant, and can pick your shots perfectly, you can make good, clean kills very easily with things like 7X57 Mauser. However, should the day not go your way, and you’re faced with trying to reach that CNS shot through the elephant’s ass? Good ‘effing luck–Like as not, someone is gonna get thoroughly trampled.

    Everything in firearms and ballistics is a compromise–The question is, which factors do you want to weigh, and what are the penalties? .22LR is a deadly, deadly cartridge–Provided you can put it into the precisely correct point, and let it do its work. On the other hand, if you’re stuck trying to make that perfect shot in a dynamic, moving environment, where the target is trying to do you in at the same time, you may find that your choice of compromise factors was exceedingly poor.

    It’s horses for courses–You don’t pick a Thoroughbred as a mine pit pony, and you don’t try to run the Preakness with a Shetland Pony, either. Making an informed choice is a result of educating yourself, and then weighing the various factors out. If you don’t do so in a sensible manner, well… That’s how we got to the FBI choice of the 10mm as a general-issue cartridge for all agents, and the subsequent failure of that program.

    And, again, I’d just like to point out the general lack of real research in this arena, particularly with regards to actual effects in direct infantry combat. Nobody really knows what the hell goes on in a firefight–What is it that creates the victory? Is it a moral factor, or is it something more calculable, like percentage of casualties inflicted on the losing side?

    Part of our problem in dominating the battlefield is that we simply don’t have an understanding of what’s going on over on the other side of the two-way range. Which of our weapons is actually delivering effect, and which aren’t? Does the enemy withdraw when we kill enough of him, or is it when the enemy feels like they’ve lost dominance in the exchange of fires? What effect will putting silencers on most of our weapons have, in an actual traditional firefight, where the noise of our weapons is as much a psychological tool as it is physical? Is it less effective to use precision semi-auto fire, in terms of psychological effect, or should we be using full-auto, volume-of-fire solutions? Which is more economical, in terms of training, logistics, and effect on the enemy?

    You go looking to dig out the data on this stuff, and good luck finding it. It isn’t there–In most cases, we don’t even know which weapons are inflicting most of the damage on our enemies, usually because we don’t bother to look. After serving at the NTC as an observer/controller, and watching innumerable engagements on the “big screen” up at division-level headquarters in Iraq, I’m convinced that most of the involved people making the reports really don’t have a flipping clue what happened in those fights. You think you suppressed the enemy; reality is something else happened, and your fires actually missed them, while someone else managed to do the real damage. There was one memorable ambush of insurgents that went bad where the LT on the site thought his troops on the flank managed to take the enemy out; reality was, their automatic rifles and squad weapons raked the hillside above, while there was an unidentified element that dropped multiple bursts of heavy machinegun fire onto the insurgents, the source of which we never identified. Strong possibility that it might have been other insurgents who were firing at the flanking squads exists…

    But, due to the fog of war, we’ll never know. That’s how it is with a lot of these things–The lab and calculation proposes, and the fates dispose, with whimsy.

  7. Kirk says:

    @Wang Wei Lin,

    The “enough holes” hypothesis is one that I’ve argued in favor of, but only for those who can’t effectively handle larger-caliber weapons. The problem with “enough holes” is that you may find yourself in a situation where you simply can’t wait for the bleed-out, or for reality to catch up with your assailant. Adrenaline gets a huge, huge vote in these things–There are enough cases where subjects shot to tatters have managed to inflict deadly effect after the point where they should have logically been stopped that I am not at all sanguine about taking a case of .22LR into a fight with someone. The amount of damage that the human body can soak up before succumbing to accumulated minor damage is awe-inspiring, and quite horrifying. I knew a Chicago cop who was present and involved in a shoot-out with a PCP-affected suspect, and they literally had to shoot some of the suspect’s limbs off in order to stop him. Ungodly number of .38 Special round, some 9mm from an Illinois State Police officer involved, and multiple hits from 12 gauge shotguns. They did not manage to put the suspect down, until they literally shot off one of his lower legs, and he was still putting up a fight on the pavement. Supposedly, once they got the antagonists and tranquilizers into him, the sudden relaxation effect just led to what amounted to an immediate and complete blood loss on the gurney.

    So, yeah… “Enough holes” will work, but the question is, how long will it take, and can you afford to wait? Me, I go for a compromise: “Enough Big Holes in the Right Places”.

  8. Old Guy says:

    This sounds as if we are exclusively talking about outdoors. If I am a homeowner I am more concerned with indoors and penetration of walls and the like. 11″ at 11 yards sounds okay as my biggest room is only 5 yards.

  9. Kirk says:

    @Old Guy,

    We’re talking penetration in people, not drywall and studs. The two are not equivalent.

    The shotgun in a home defense situation may not be optimum, especially if the homeowner is essentially doing a tentative house-clearing to determine whether there is a need to hole up and then call the the police to deal with an intruder. A shotgun gives an intruder too much leverage to use against a homeowner if they can get within the muzzle zone of the weapon and grab it. For this reason, I would only recommend a shotgun for a scenario where you are defending a fixed area and waiting for the intruder to come inside the range of fire. Clearing a house with a shotgun is s fool’s game, unless you have no other choice.

  10. Brad says:

    This video seems to show #4 buckshot penetrating adequately beyond 20 yards. Even at 40 yards, the most frequent pellet penetration was 11 inches in ballistic gelatin.

    https://www.youtube.com/watch?v=3VTk_7884r8&ebc=ANyPxKovNLWrv5UEZsGemKk93aiOSjgXWdPlq-F310juC13b87QbtPFouBF3gWRr-WSgmL8lYZ_u

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