Oct 162011

Shot pattern approaching the end of the gun's B zone, image from www.stu-offroad.com/firearms/patterntest/buck1-1.htm

There are a lot of misperceptions about shotguns – perhaps more so than exist about rifles or pistols.  We addressed this topic before – see our article ‘Correcting Some Misinformation About Shotguns‘ for some helpful information about what they can and can’t do.

We got into the middle of a conversation about shotguns yesterday.   A client was considering buying a shotgun, and another person was advising them about shotguns.  Unfortunately, the advice wasn’t very accurate.  The first comment perpetuated the myth that shotgun rounds spread sufficiently at short ranges as to guarantee you an effective hit on your target, even at close range such as inside your house.

As our earlier article explains, at a 20′ range, a 00 buck load will spread to perhaps 4″ in diameter.  That is of course better than firing a single pistol round, but it is a long way short of guaranteeing that your shot will effectively strike the target.  While the shotgun advocate didn’t say exactly how much spread he thought a shotgun round would experience at short-range, it was clear he was expecting it more like a foot or two rather than an inch or two.

This leads on to an interesting topic that we did not consider in our earlier article about shotgun misperceptions and also follows on from the next piece of advice this gentleman volunteered – what is the maximum effective range of a shotgun?

His answer was ‘Oh, about over to that bush there’ – a distance of maybe 30 ft.  He was again wrong.

Let’s first of all understand what determines the maximum effective range of a shotgun, then decide what that range actually is.  Note that in this discussion we’re primarily considering self-defense situations, rather than the maximum range you’d get if duck shooting or using the shotgun in some other type of situation (shotguns designed for bird shooting will have much longer effective ranges than shotguns designed for home defense).

There are four factors influencing the maximum effective range you’ll get.

Definition of ‘Effective Range’

The first thing to consider is what is meant by ‘effective’ range.  Do we mean the maximum range at which the shotgun remains reasonably accurate, or reasonably lethal, or something else?

Let’s define effective range as being the maximum range where a shotgun is both sufficiently accurate as to give you a high probability of scoring a hit, and with the hit you score being sufficiently lethal as to take your adversary out of the fight.  This dual factor definition reduces the range substantially below the theoretical maximum range.

Shotgun Barrel Length and Choke

A shorter barrel on your shotgun will cause the shot to spread more rapidly, and the more rapidly the shot disperses, the less the gun’s effective A and B zone ranges will be.

A shorter barrel will also result in slightly less of the energy from the explosive charge in the shell being used to push the shot out of the barrel.  A longer barrel obviously is the opposite – a tighter pattern (better A and B zone ranges) and slightly more energy from the shell is passed on to the shot (better C zone range, too).

The minimum length of a shotgun barrel, by law, is 18″; at the other extreme, you can get sporting shotguns with barrel lengths up to 34″.  That’s a huge range of different lengths, but for home defense purposes, you’ll be wanting something short and easy to carry/point with – 18″ – 20″, ideally.

Just so you know, there are two exceptions to the 18″ minimum barrel length requirement.  The first exception is if you get a special federal license for a shorter barreled shotgun.  The second is if you have a shotgun with a shorter barrel but a permanently affixed ‘flash suppressor’ type device on the end, so as to bring the length of barrel and flash suppressor up to the 18″ minimum.

A barrel’s choke refers to if it has an internal taper.  Some shotgun barrels have an internal taper, such that the barrel gets narrower in the last few inches as it gets closer to its muzzle (the end which the shot comes shooting out of).  If the barrel has some internal tapering, then it is said to have a choke.  If it has no choke at all – if the diameter of the barrel is the same all the way along, it is said to have a cylinder bore.  All pistols and rifles have no choke, but unlike rifles and pistols (which have rifling in their barrels) a cylinder bored shotgun has a smooth bore barrel.

The purpose of the taper or choke is to cause the shot pellets to spread more slowly.  This can be useful when shooting at birds from a distance, but it is less useful in a home defense situation, where distances are very short, and you’re probably hoping for a good deal of spread to compensate for any lack of perfect aiming.

A barrel with choke can not be used to fire slugs.

There are many degrees of choke, and they are usually described by name.  Those names that include the word ‘Full’ in them have the most choke, with the least amount of choke being possessed by a Skeet type choke, followed by Improved Cylinder, then various types of ‘Modified’ before progressing on to Full choke types.

To give you a feeling for the impact choke has on spread, you can get twice the range for the same degree of spread from a barrel with a Light Full choke than you could from a barrel with a Skeet choke.  Bearing in mind there are even tighter choke options (and also the unchoked option too), clearly the choke has a big impact on spread and therefore also on effective range.

Which brings us to the next point.

Spread – How Much Shot is On Target

Some spread is a good thing when firing a shotgun, because it gives you a broader ‘cloud’ of pellets when they reach the target.  If they all hit the target, you’ve scored multiple hits in multiple parts of the target; potentially causing multiple wounds to multiple organs and speeding the rate at which the adversary is incapacitated and taken out of the fight.

And if your aiming is slightly off center, hopefully the spread of the shot will be enough so that some of the pellets will still hit the target, on the basis that ‘some is better than none’.

The biggest real world advantage of a shotgun is with a compact cloud of pellets all hitting the target.  The biggest hoped for but imaginary advantage of a shotgun is the incorrect expectation that the expanding cloud will reduce the need for careful aim.

If you’re firing 00 buck from a 2 3/4 inch shotshell, you are probably shooting nine balls, each comparable to a .380 bullet, at the target.  You could accept a few missing the target as long as most hit, and still have an excellent chance of winning your encounter after firing a single shot with less than nine (but more than one or two) of the balls hitting the target.

Now for the swings and roundabouts of spread.  Clearly, some spread is good.

But, equally clearly, too much spread is bad.  For bird shooters, too much spread can mean that the distance between each pellet becomes so great that a bird can fly through the gaps unharmed.  In a home defense situation, it can mean that instead of landing nine balls on your target, or eight, or seven, you might end up with only one or two reaching the target, and the others all flying harmlessly off somewhere else (or – even worse – going harmfully off, through other rooms in your house/apartment and risking anyone else there, and continuing on into your neighbor’s house/apartment, risking anyone there too).

These issues are recognized in the transition from your shotgun’s B zone to its C zone, discussed below.

The Type of Round being Shot

If you’re firing bird shot through your shotgun, then the first thing you should do is replace it with buckshot!  You’re not seeking to defend yourself against vicious attacking birds.  You’re seeking to defend yourself against vicious attacking people.  If you are firing birdshot, it becomes ineffective pretty much at the end of your shotgun’s A zone (see below).

If you’re firing buck shot, it is a good solution all the way out to the end of your shotgun’s B zone.

And if you are firing solid rifled slugs, you’re in good shape – and your adversary is risking transitioning to becoming in very bad shape – all the way out to the end of your shotgun’s C zone.

And now for the part you’ve been waiting for – an explanation of these three zones.

The Three Shotgun Distance/Range Zones

A shotgun’s pattern/effect/spread is typically described in terms of three different sets of ranges or zones.

Note that these zones are only loosely defined, and also vary greatly depending both on the shotgun you are using and the ammunition you are running through it.  But understanding this three zone concept is a key part of understanding your shotgun and how best to use it, because the three different zones require different tactics and – ideally – different types of shot shell load (or slug) too.

Shotgun A Zone

The A zone starts from the muzzle and typically stretches out 5 – 7 yards.  This zone is defined as being where the individual pellets or balls travel closely together, with very little spread.

Because there is so little spread, when you are shooting your shotgun at a target in its A zone, you need to aim and shoot it as carefully as you would a rifle or a pistol.

We never recommend you use birdshot in a shotgun – birdshot is, as its name clearly expresses – designed for shooting birds, not for home defense.  But within the A zone, your shotgun is likely to delivery a tightly compressed pattern of birdshot that is only slightly less solid in effect than being hit with a single shotgun slug, and so if you have nothing else, you could use birdshot within your gun’s A zone.

Shotgun B Zone

Your shotgun’s B zone starts from the end of the A zone and typically extends out to about 20 – 25 yards (assuming a cylinder bore on your barrel).  It is hard to say exactly where the A and B zones transition, but it is easier to determine where the B zone ends.

The B zone ends at the point where the spread of balls is greater than the size of the target you are aiming at.  In a self-defense situation, you’ll be aiming for the center of the thoracic cavity (the chest, if you prefer a simpler term).

Remember we said you need to aim your shotgun very carefully while shooting in the closer A zone?  Unfortunately, you ‘re going to want to aim your shotgun very carefully in the B zone, too.  Although the spread of shot is increasing, so is the distance, so just a ‘smidgen’ off in your aiming will have greater effect in where all the shot lands downrange.

Even at the end of your B zone – say 20 yards/60 feet – you’ve only got a spread pattern that is maybe 12″ in diameter.  In other words, your pellets will spread in a pattern extending out about 6″ to the left, right, above and below your aiming point.  That means that best case scenario, you can only be 6″ off in your aim if you want to get sufficient of your shot pellets on target.  And at 20 yards away, 6″ isn’t much leeway for your aiming.

Shotgun C Zone

So what happens at the end of your shotgun’s B zone?  Yes, of course, that is where the C zone starts.  The C zone is the area where you are best advised to stop shooting buckshot and switch to solid slugs.

The C zone starts at the end of the B zone, which you’ll recall from the preceding paragraph is where the individual balls of buckshot are starting to spread out so that not all of them are landing on the target.  Just as with the transition from the A to B zone, this is a fairly vague sort of distance.  It also can’t be stressed too much that the distance can vary enormously depending on your shotgun, its barrel and the loads you are firing – the same gun might have a 15 yard B to C zone transition with one type of ammo and a 25 yard transition with a different type.

The C zone extends from this point of transition out to about 100 yards.  Somewhere beyond 50 yards, and probably not much further than 100 yards, your ability to get a reasonably accurate hit from a slug is going to diminish to the point where it is no longer worth taking the shot.

We should also add that, in a self-defense situation, there are very few scenarios where you would be validly shooting at people 100 yards away anyway!

For those people who have been waiting for the point where the shotgun’s mythical ‘no need to aim’ super-powers take over, we have more bad news.  So far we’ve analyzed that you need to do careful aimed shooting in the shotgun’s A zone and also in its B zone.  Guess what?  Now that we’re in the shotgun’s C zone, and we’ve switched from multi-pellet shotshells to single round slugs, the shotgun no longer offers any spread or related benefits at all.  Quite the opposite.  You now find yourself firing single slugs from a shotgun with perhaps only the most basic and rudimentary of sights.  You’ll still have to aim very carefully.

The Fallacy of Shotgun Patterns/Spreads

Many people think that it is a very good thing that a shotgun spreads its pellets or balls out over a broad area.  They see the benefit, but don’t consider the two trade-offs associated with the benefit.

The benefit is, of course, that a spread of shot means that your odds of scoring at least a partial hit on your target improve.  If a pistol or rifle bullet misses its target by even a single inch, it has no effect whatsoever on the target (other than perhaps a psychological one, and even that is far from certain – in the adrenalin maxed out situation of an exchange of gunfire, your adversary quite likely won’t even notice shots going close by him).

The reasoning goes that ‘half a loaf is better than none’ – it is better to get some amount of a shotgun load onto your target than it is to miss it entirely.  There’s some truth in this.

But what about the remainder of the buckshot you fired?  Where is that going?  Is there something behind the target or near to the target that could be damaged/destroyed?  Remember that 00 buck will readily penetrate six pieces of sheet rock – that’s enough to go through probably every other room in your house/apartment and still be dangerous when it flies on out into the open ground outside.

And while getting half your load onto your target is good and better than not hitting it at all, it is also not as good as getting all your load onto the target.

Consider also that as the spread of the shot expands, so too does the distance to the target.  So while the shot is more spread out at say 20 yards compared to at 10 yards, the target is also twice as far away and therefore twice as small (or ‘hard to hit’).  The growing size of the spread does little more than only partially compensate for the shrinking size of the target.

There’s another factor too.  Most shotguns have very basic sights on them, making it harder to accurately aim them in the first place.

As you’ve seen in the preceding analysis of tactics for engagements in a shotgun’s A, B and C zones, you need accurate aimed fire at all distances and in all situations.

The bottom line is that a shotgun is not a magical cure-all solution.  Most of all, it won’t compensate for lack of training and poor accuracy on your part.  You still need to practice with it and get competent at using it.

Summary – So What is the Effective Range of a Shotgun

Now that you’ve read the entire article, let’s compress it into a single sentence.  The practical/effective range of your home defense type shotgun, with 00 buckshot, is about 20 yards.  If you’re confronting adversaries further away, switch to a rifle, or – failing that – use solid rifled slugs in your shotgun.

  9 Responses to “The Maximum Effective Range for a Shotgun”

Comments (9)
  1. Tell me about “rifled slugs.” I reload primarily with buckshot (using long-lived brass shells for my 12 gauge shotguns). I don’t have a “slug gun,” but have a mold for rifled slugs. Can I safely use them in my unrifled shotguns? That may sound ignorant of me. I have been shooting for years. I sometimes load .72 round balls (circa “Brown Bess” years) in my 12 gauge shells, and they seem to work fine. They are right about 1 ounce. I normally use black powder (80 grains) in these loads and for the buckshot, too. I may swutcih to Unique powder at some point.

    Additionally, I am now reloading for a Taurus Judge “Public Defender” with the 2″ barrel. I’m getting better with the .45 Colt reloads, and am about to start reloading buckshot in the .410 brass shells I’ve ordered. I shot a couple of rounds of commercial buckshot shells and was not terribly impressed at 30 feet. A friend told me about splitting the buckshot and connecting them together at about 2″ intervals with monofilament fishing line. I may experiment with that and see what it does to keep the shot together. I believe that I can get four 000 Buck in the brass for .410, although the standard is 3 pieces.

    What do you think?

    • Hi, Max

      Thanks for your interesting comments.

      What would you want to use rifled slugs for? In a self defense situation, our preferred choices tend to be pistols at close range and confined spaces, shotguns with buckshot at medium range, and rifles for anything further out. Actually, ideally we’d use a rifle everywhere, always, but there are usually other issues interfering with the ‘perfect world’ choice.

      A rifled slug strikes us as being the worst rather than the best of both worlds. They lose energy fairly quickly, and while in theory they are accurate to 100 yards or so, the chances are you don’t have sufficiently good sights on your shotgun to shoot it well.

      Making bolo type rounds for the Taurus Judge is not something we’d recommend. We can hear the prosecution now, thundering to the jury, about how you had hand-made these special deadly mankilling rounds for the gun. They are illegal in some jurisdictions (we think) and they sound bad when you’re having to justify the dead guy you’re standing next to. Even if you get found not guilty, your chances of being prosecuted for something go up when you start using unusual custom handloads.

  2. Very interesting article. I particularly like the conservative estimate of 20 yards. In just about every discussion, shogun effectiveness is based solely on pattern. The pattern-only approach assumes that if the pattern is good, the energy will be sufficient to support penetration, but that certainly isn’t a given.

    For example, what is called low recoil ammo, is really reduced power ammo. A standard 2-3/4″ load of 9 00 pellets has a muzzle velocity of 1325 fps; low recoil starts out at no more than 1200 fps. At first look that doesn’t seem like much, but it is. In order to bring the low recoil energy up to the standard load energy, you would have to increase the low recoil energy by 34%! Winchester even states that their low recoil has 30% less recoil. Well that also means 30% less energy out the muzzle.

    At 25 yards, the pellets have separated from each other and act as single projectiles. I strongly agree with what you said about the spherical and flattened shape losing velocity rapidly. So a 00 pellet ( a mere 54 gns) starting out at 1145 fps (Federal 132 00) at the muzzle would probably be down to at least 1000 fps at 25 yards. Each of the 9 pellets would experience this loss in velocity. A 54 gn pellet traveling at 1000 fps only has an energy of 120 ft-lbs! That’s astonishingly low power.

    Some would say, “So what?”, so I’ll explain. It is energy/momentum that drives the pellet into the medium, be it flesh or ballistic gel. How far would 120 ft-lbs drive a 0.33″ pellet into ballistic gel? Not very far.

    Some would say, “There are 9 pellets though, not just one.” That’s true but all the pellets have the same low energy and the inability to penetrate sufficiently. Nine pellets won’t increase penetration. It increases shallow wounding which may be enough.

    There is an anecdotal incident where a BG was shot with low recoil at 40 yards – that’s pushing the range, but…when they examined the BG, the pellets had not even penetrated his ‘cheap’ leather jacket. Again that is stretching the range, but it shows clearly how quickly pellets lose energy.

    Based on all I’ve seen, analyzed and read, I limit low recoil loads to 15 yards or less. I think you were right on with your estimate of 20 yards for standard 00 loads.

  3. As a defensive shooter, the goal isn’t always to make a fatal shot, but to eliminate the threat.

    I’ve carried everything from a 380 to a 12 gauge up north loaded with slugs for bear and carry a lifetime of experience with guns that started with my dad’s 22 snub and 36 chief. I carried a 20 gauge until I was in my 20’s and still made more game harvests than most of my friends whose carried the more abusive 12 gauge.

    The goal of a defensive shooter isn’t always to kill the other side. It’s to eliminate the threat. I’ve heard the argument so often that shotguns are ineffective unless they’re loaded with buckshot or slugs, but never discount bird shot the way many people do. One or of shots with an ounce of bird shot will definitely make an intruder think twice about whether they want you to shoot them again at any range up to 30 or 40 yards. If they do, there isn’t a gun out there short of a 105 howitzer that’s going to do much good so you really might need to invest in some good running shoes.

    I’ve seen all calibers fail and all calibers kill. It’s really not a predictable science because the two key variables that determine the outcome (shooter and person being shot) are such wildcards, I’ll stick with my Glock and my shotgun without hesitation. They both beat a big stick and can at least give me a head start out of the situation.

    As a boy, I’ve always tried to keep my shots below fifty yards with anything except a rifle (75-100 yards). It doesn’t do anyone much good to shoot game at 500 yards because you then have to retrieve it. My rule, never shoot anything any further away than you’re willing to drag it back to the car.

    • Dave…as a defensive shooter, you sure as hell BETTER want to hit that intruder. Intruders often have weapons of their own. And a scared one that is barely hit by birdshot can and will fire back at you and may hit his target a little better.

  4. This new, improved, fat-free/sugar-free/vitamin-fortified shotgun dogma is not without flaw–but perhaps it is more reality-based than the old “you need not aim a shotgun” dogma. The American military still lists #00 buckshot from a 12-gauge riot gun as having 50 meters effective range (55 yards). “Effective” means different things to different people. The US Army regards a single buckshot strike as “incapacitating” and the US Army Medical Corps set a 58 foot pound minimum energy level (if I remember correctly).
    Police shotguns are generally restricted to just the four shots in the magazine–and low-recoil #00 buck came about because of all the shotguns with those brutal metal folding buttstocks. Police have to worry about the lawyer attached to every projectile launched down-range; more than one department’s shotgun doctrine gives an 18-yard effective range–if not a mere 15 yards. One reason for the police shotgun is it “out-ranges” the police sidearm. Few police departments fire their sidearms in qualification at distances beyond 25 yards, and many draw the line at 50 feet. Basically, police trainers want EVERY projectile to hit the qualification silhouette. Some low-recoil #00 buckshot shells have only eight of those .33 caliber balls. Police are lawyer-shy and worry more about liability than about turning off bad-guy aggression–for good reason. That is a major reason for swapping police shotguns for patrol rifles: single projectiles versus a swarm of random pellets.
    For deer hunting, many experts recommend keeping all shots inside 25 yards–with a standard charge of buckshot (not low recoil). Utah big game hunting regulations restricts buckshot to #00 out of penetration concerns.
    “Home defense” is yet another kettle of fish. Old school defensive advice to “get a shotgun” was predicated on the near-universal presence of the scattergun in rural households, a gun that was used often, that the homeowner already knew. Note that no specific load was mentioned–the shotgunner already had pet loads for his blunderbuss. Why buy a handgun (good only for “killin’ people”) during the pacifistic Twenties and Thirties when the shotgun was already on hand and the owner was skilled? Now that is obsolete advise because the homeowner is just as likely to be equally ignorant of shotgun, handgun and rifle. That’s how people think that snake loads in a .38 turns their snubby into a 12-gauge riot gun, or that the .410 is acceptable as a home defense shotgun when shells contain either 3 or 5 #000 pellets (in 2-1/2″ and 3″ .410 bore shells). The .410 rifled slug has very low energy–86 grain Foster slug at an advertised 1830 feet per second (really?) churns up nearly 640 foot pounds energy, but getting factory spec muzzle velocities is unlikely, especially from something like a Taurus Judge. If you want 12 gauge performance, get a 12 gauge shotgun. And then remember that “deadly force” must be justifiable (the court is the designated Monday Morning Quarterback that will determine if your use of deadly force was JUSTIFIED) which means you can only counter an immediate threat of deadly force–and generally, that means staying inside your house. How many feet across the living room? A thirty-foot shot down a hallway is a long distance.
    I’m going to rush in where angels fear to tread and claim that for the private citizen, the maximum effective range of the shotgun is the far edge of justifiable deadly force distance. Depending upon the political climate in your area, that may be as little as 7 yards–or in excess of 25 yards. Even though an improved cylinder bore shotgun may have two or three #00 buckshot stray off a silhouette target at the far distance, a human receiving five or six or seven #00 buckshot at distances under 50 yards isn’t going to be very healthy. Buckshot has greater range than the justifiable deadly force used in self-defense distance.
    Low recoil buckshot tends to pattern more tightly than sporting buckshot and the lower recoil impulse reduces flinching and allows more rapid re-aiming on target. Go to a gas-operated autoloading shotgun and the “tactical” buckshot has enough energy to cycle the action along with trap load recoil. Penetration with the low recoil buckshot is deeper than imagined because tactical buckshot doesn’t deform as much as the sporting buckshot–and the greater the divergence from bore line, the more velocity the buckshot pellet has shed. At 1200 feet per second muzzle velocity the 53.8 grain #00 buckshot pellet has 172 foot pounds energy–at 100 yards this is 879 feet per second (nominal) and 92 foot pounds energy–but the pattern is spread out so much that at 100 yards all pellets might miss. Regular buckshot has higher velocity.
    Even a 20 yard “maximum effective range” is probably going to set the prosecutor on your tail for miss-use of deadly force.

  5. Little mistake here:
    “Consider also that as the spread of the shot expands, so too does the distance to the target. So while the shot is more spread out at say 20 yards compared to at 10 yards, the target is also twice as far away and therefore twice as small (or ‘hard to hit’).”

    Actually, if it’s twice as far then it is four times smaller, not twice, since it’s both half tall AND half large. For example, a target that appears as 6×2 feet at 10 yards will look as being 3×1 feet at 20 yards. That’s down to 3 feet square from 12 feet square.

    • It isn’t four times smaller, it’s exactly the same size. It’s further away so it looks smaller but it’s the same size.

      Let’s take a laser (to eliminate any effect of bullet drop) and focus the laser on the top edge of a 2″ target at 50 yards, i.e. it is one inch above the center of the 2″ target. Leaving the laser at the same position, we move the target to 100 yards. How high will the laser be from center? Two inches. How large would the target have to be for the laser to be right at the top edge? Well, if it’s two inches above the center, then the target would have to be 4″. But we started with a 2″ target at 50 yards. Hence the target ratio is 2:1, not 4:1.

    • Lyzi,

      It just occurred to me what you were referring to – pellet density. I was addressing shooting error. You are right. If we double the distance, the pellet density changes by a factor of 4. Of course that assumes linear pellet spread with distance and that seems reasonable.

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