Pique the Geek 20110213: Firearms 102. Shotguns

( – promoted by TheMomCat)

I was astonished at the response for the first installment for this series, and so decided that instead of just a couple of survey pieces, reader interest justifies a bit longer treatment, getting more into the weeds. Thus, I have come up with a bit more structured series.

Unlike rifled firearms like pistols and rifles, shotguns are smoothbore weapons. That is, they have no rifling to impart spin to stabilize the projectile, in the case of shotguns usually multiple projectiles. Shotguns are a relatively recent development in their current form, but the concept of firing more than one projectile at a time goes back a very long time.

Modern shotguns are designed to fire a relatively large diameter cartridge as opposed to rifles and pistols. In addition, a different system is used to state the diameter of the cartridge in most cases.

First, a word about firearms in general. They, by design, are LETHAL weapons and must always be treated with respect. My assumption is, and I think that it is a good one, that all of my readers who are firearm owners are responsible with them and careful with them. However, it is all to easy to get complacent, as my story about my own father in the comments last week at the big orange, here, indicate. You keep them away from your kids, and when those kids are old enough to learn about them, you carefully teach them, but NEVER without the utmost supervision. For those of you who do not own firearms, you obviously do not need to go to those measures, but as Kossack yesdevkmem pointed out in the comments there last week, you still have some responsibilities. I thought that comment was so important that I promised to lead with it and to credit yesdevkmem with the idea.

EVERYONE, both firearm owners and those of us who do not own them, that has children need to heed the words to the wise that xxxx gives. Here is a paraphrase.

In the course of playing outside, there is a possibility that one of your children, or one of their friends, might come across a firearm that has been for whatever reason, within their reach. You need to teach them these rules:

DO NOT TOUCH IT! EVER! If your child does not touch it, and prevents any friends from touching it, it can not hurt them. In addition, abandoned firearms are often crime scene evidence, so touching one makes investigation more difficult.

GET AWAY FROM THE AREA IMMEDIATELY! Whoever ditched it might still be nearby, and almost always those are dangerous people. Second, the longer that they are nearby, the more that they contaminate the site for possible forensic investigation.

GO HOME, or to the home of a trusted adult, and LOCK THE DOORS! This is mostly because of the possibility of a nefarious person still being nearby.

TELL YOUR PARENTS! They will contact the authorities and report it to them. If that is not possible, they should tell another trusted adult. Since time is often key to solving criminal activity, if that is not possible, CALL 911 and REPORT IT!

People do not just “lose” firearms. I know of only ONE legitimate instance from personal experience, and it had to do with a boat sinking in water too deep to attempt to recover the firearm. The value of the firearm was low enough that he just let it go. Almost without exception, firearms found in odd places are either stolen and the thief got cold feet, were involved in a violent crime, or otherwise had some nefarious connexion. Please, all of you with children, teach them these lessons. That also applies to adults who happen on to one, except for the telling your parents part. Safety message completed.

Shotguns are amongst the most common sporting firearms, being used for birds of all kind and other small game, like squirrel and rabbit. They have a major advantage over rifles and pistols, particularly for fleet game, because instead of only one projectile, many are ejected from the muzzle of the firearm. This has the advantage of increasing the probability of at least one pellet hitting the target, and for small game one is often enough.

Shotgun cartridges (called shells, shotshells, or shotgun shells) come in many different sizes, and within each size a wide variety of configurations can be had. For example, one can have a 12 gauge shell loaded with an ounce of “00” buckshot (diameter of 0.33 inches) for a total of nine shot, or for the same mass of lead, #8 birdshot (diameter of 0.1 inch) there would be 420 pellets. Obviously, the nine 00 buck each have much more knockdown power, but the coverage at a given distance is greater for the #8 bird.

Since I mentioned a 12 gauge shell, we might as well discuss what gauge represents. It is an old term from England, and nominally is equivalent to the number of equal lead spheres that can be had from one pound of lead. Thus, 12 gauge means that the pound of lead would yield 12 spheres of a specific diameter, in this case 0.729 inches. Thus, a 10 gauge has a larger diameter (0.776 inches). You rarely see anything larger than 12 gauge any more. The 12 and the 20 gauge (0.614 inches) are by far the most common gauges these days. Not too many years ago the 16 gauge (0.663 inches) was extremely popular. My father was an avid upland bird hunter and loved his side-by-side 16 gauge Parker above all others, considering it the best compromise betwixt weight and firepower for his use.

There are two other “gauges” that actually calibres, fractional inches. The most common is the 0.410 (this comes to about 68 gauge), often used for close range shooting of slowly moving game such as squirrel. The other is the 0.22 calibre, with very fine shot, often used in .22 rifles. In this configuration they are often called rat shot. Also found now and then are 9mm shotguns, around .36 calibre.

I mentioned that gauge is nominally the number of lead balls of equal size that can be obtained from a pound of lead, but the relation is not exact, and now the actual internal diameter of the chamber is standardized and is not quite the same. Also, because of the choke of a shotgun barrel, the muzzle end if often somewhat smaller than the breech end. Choke is an extremely useful property of a shotgun, as it controls the density of the shot pattern. As soon as the shot leaves the muzzle of the firearm, it begins to spread out in essentially conical fashion, meaning that the further away from the muzzle you look, the larger the pattern. On the other hand, the larger the pattern, the lower the density of the shot. Choking the barrel increases the density, and decreases the size, of the pattern. The standard distance to determine choke is 40 yards, and the target is a 30 inch circle inscribed usually on paper.

The choke in a barrel is simply a constriction (pretty slight) that essentially acts as a lens to “focus” the pattern into a more dense arrangement. This becomes important when longer ranges are desired. For a barrel with no choke at all (called cylinder), typically 40% of the pellets will fall into the 30 inch circle if the shot was aimed correctly. That means that 60% of the shot is way off target. Cylinder choke is used only for very close range work. On the other hand, at very close ranges a much tighter pattern would make it easy to miss the target, so just because there is not any choke does not mean that it is of no value, rather that its utility is at very close range.

Towards the other extreme, full choke is expected to have 70% of the pellets within the 30 inch target. This is useful for longer ranges, but requires very good shot placement to get hits at short ranges. In addition, at short ranges a full choke hit tends pretty much just to blow up whatever you hit, ruining the game that is taken to a large degree. Now, it does not take much barrel constriction to provide full choke, only about 0.035 inches. The constriction is best a gradual one, because if it is too sharp, the soft lead pellets tend to become deformed, and this decreases the quality of the pattern.

There are lots of other chokes, the most popular of which are probably improved cylinder and modified. Those produce 50% and 60% of the pellets, respectively, in the 30 inch circle. It is possible to add a device that screws onto the end of the muzzle that has interchangeable choke inserts, so one shotgun can perform the functions of several. Like most jack of all trade devices, they are usually not as good as a specific weapon, but can do some good.

This is why so many shotgun hunters love their double barreled shotguns. One barrel can be fashioned in one choke, and the other in a tighter one to give you a second chance to hit the bird that you missed as it flies away from you. However, there are other configuration.

The two basic types of shotguns are the break action and the internal action types. In the break action type, which includes single shot and double barrel firearms, after one or two shots have been fired, a lever is pushed that allows the breech to pivot away from the firing pin ports so that the spent shells can be removed and new ones inserted. The higher quality models have “automatic ejectors” that “know” which chamber(s) has been fired and ejects only the spent shells.

Double barreled shotguns can be either of the side-by-side type of the over-and-under style. The difference is, obviously that in the first type has the two barrels arranged horizontally whilst the second type has them in a vertical configuration. Personal preference seems to be the key to which is “better”. My father swore by side-by-sides, whilst I strongly prefer the over-and-under kind. I strongly suspect that the fit of the individual weapon to the shooter is more important than the barrel configuration.

Internal action shotguns are of two basic kinds: the pump action and the automatic (actually, semiautomatic). Both styles have an internal magazine, typically holding five rounds, but for special purposes other capacities can be had, and a single barrel. In the pump action, the forestock is pulled towards the shooter and then pushed back to chamber the first round (or a sixth can be chambered manually). After firing, the slide is pulled and pushed to eject the spent round and chamber a new one.

In the automatics, the final round has to be chambered manually, and some of the energy released during firing is used to eject the fired round and chamber a new one, as long as a new trigger pull is performed each time, until the magazine is empty. For both types, most states require that a “plug” be inserted into the magazine to limit the capacity to three rounds when used for hunting.

A shotgun cartridge consists of an outer casing (usually plastic with a metal base to hold the primer), the primer at the breech end to ignite the main powder charge when struck by the firing pin, the powder charge (which can be varied both by type of powder and amount for different performance ratings), a wad (usually injection molded polyethylene, but formerly fibre stock and/or paper), and the shot charge, which can also be varied by size of shot as mentioned before, and by total amount of shot. The so called three inch magnums are longer than the standard shotgun rounds and generally carry heavier loads both of powder and shot.

For waterfowl shooting, lead shot is now banned by Federal regulation, so other shot material has to be used. Steel shot is the standard replacement, but has some serious deficiencies. Since it is less dense than lead, to get the same penetration, larger shot has to be used. Larger shot means fewer shot, so steel shot is not ideal. Several substitutes are in use, including bismuth (good performer but expensive) and tungsten/polymer composites. These perform more like lead shot, but are much more expensive.

Well, you have done it again! You have wasted many more einsteins of perfectly good photons reading this scattergun post! And even though Bill O’Reilly admits that he is not the champion wordcrafter when he reads me say it, I always learn much more than I could ever hope to teach by writing this series, so please keep those comments, questions, corrections, and other ideas coming. Remember, there is no such a thing a being off topic when addressing any science or technology subject in the comments.

Warmest regards,


Featured at TheStarsHollowGazette.com. Crossposted at Antemedius.com and at Dailykos.com


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  1. this scattergun approach to a post?

    Warmest regards,


  2. Says that people are owned by the state.  You as a citizen agree to be contractually bound by and to the state  by registering your car, house, social security numbered IRS tax returns, voter registrations and a host of other items which label you as a subscriber to a local, state and national “community”.

    Now outside of “the community” having that capacity to nuclear winter earth seven times over 29 years ago the very thought of mere peasant individual citizens having primitive firearms has taken on such a negative connotation.  It is as if all of us peasants are striving towards honorable mention in the Darwin Awards or are just too Charolette Iserbytian to handle such fearsome weaponry.

    Or is it just that we might screw up the profit margins of some insurance company or the inconvienient expense of some medical establishment treating bullet wounds.  I mean, really, it’s not like they care, have that capacity to care about other people.

  3. mum!  Firearms are an integral part of our culture, and using them safely is extremely important, as is knowing what they are.

    Warmest regards,


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