“Use a shotgun… and you don’t kill your kids.”
– Joe Biden: Vice President of the United States of America –
- Introduction To Shotgun Ammunition
- What is Gauge?
- Shotshell Parts & Markings
- Rifled Slugs
- Sabot Slugs
- 2.75″ vs. 3″ Shells
- High-Brass vs. Low-Brass
- Reduced Recoil Shotshells
- Specialty Rounds
Introduction To Shotgun Ammunition:
What is “Gauge”?
The “caliber” of rifle and handgun ammunition refers to the diameter of the bullet in 100th or 1000th of an inch. The bigger the caliber, the wider the bullet. Shotguns are different. Instead of caliber, shotguns barrel diameter is expressed by “gauge”. Gauge is defined as a unit of measurement used to express the diameter of the barrel and is determined from the weight of a solid sphere of lead that will fit the bore of the firearm, and is expressed as the multiplicative inverse of the sphere’s weight as a fraction of a pound (e.g., a 1⁄12th pound ball fits a 12-gauge bore). Thus there are twelve 12-gauge balls per pound (etc.). Opposite of caliber, the bigger the gauge of a shotgun, the smaller the diameter of the shotgun shell. (So 28 gauge is smaller than 20 gauge, which is smaller than 16 gauge, which is smaller than 12 gauge, which is smaller than 10 gauge, which is smaller than 8 gauge.)
.410 is the smallest size shotgun. After all the discussion on the definition of gauge, it is interesting to note that “.410” is actually the caliber of the shotgun rather than the gauge. .410’s have very little recoil and are good for teaching young shooters the fundamentals of shooting shotguns, and for taking care of snakes and rodents at close range. It is generally not adequate for self-defense, although I don’t know of anyone that wants to be shot with one.
28 gauge, 16 gauge, 10 gauge, and 8 gauge shotguns are for hunting. There aren’t any over-the-counter combat / defensive shotguns in these sizes that I am aware of. Most of these gauges of ammo are fairly obscure and not readily available Wal-Mart, and since the ease of proliferation is one of my criteria in the selection of a defensive weapons system, I would not consider one these for defense.
12 gauge is the standard for combat/defensive shotguns. 12 gauge makes up 50% of the shotgun market in the U.S. The great majority of combat/defensive shotguns are made in 12 gauge, with a few made in 20 gauge. 20 gauge may be used by smaller frame or disabled shooters, however it lacks the kick-ass factor of 12 gauge. Anything smaller than 20 gauge is not appropriate for self-defense.
Shotshell Parts and Markings:
Shotgun shells have five basic parts:
- The hull or shellcase
- Wad or shot cup
- Projectile (Shot, pellets, or slug)
Types of Shotgun Shells:
The three most popular types of shotgun shells are:
- “Slugs” (sabot slugs or rifled slugs)
There are also many types of specialty rounds which include flares, CS, incendiary, etc.
Birdshot (as seen on the left in the photo below) fires a dense cloud of very fine pellets and is intended for shooting flying birds or sporting clays. There are different size shot for different applications (as seen right). The smaller the numbering of the shot, the finer the pellets and the greater the number of pellets that can be crammed into the same shotgun shell. (#8 shot is the finest birdshot, and is finer than #6 shot, which is finer than #4 shot.) There are also heavier shot loads intended for hunting duck and geese. Note that the smaller the shot, the less mass each pellet will have, which will result in less kinetic energy on the target and less effective range of the pellet. Hunting thick feathered geese will require heavier pellets than hunting dove or quail. Birdshot is very deadly at close range, but it quickly looses its energy and becomes an ineffective defensive round.
Do not confuse birdshot with buckshot. For example, “#4 birdshot” is not the same as “#4 buckshot”. Buckshot is discussed next.
|Size||Pellets Per Ounce – Lead||Pellets Per Ounce – Steel||Ideal Use|
Buckshot (as seen on the right in the photo above) is intended for deer hunting and self-defense. It is filled multiple round projectiles that when fired will hit the target simultaneously. Buckshot is made with different size projectiles, depending on the intended application. As with birdshot, the smaller the pellets, the more that can be loaded into the shell . As noted in the illustration to the right, the bigger the numbering of the shell, the smaller the projectiles. 000, or “triple aught”, has the largest size projectiles. 00, or “double-aught”, is the general self-defense load. With a 2 ¾” shell there are nine 33-caliber lead balls loaded inside. #4 shot has a greater quantity, but smaller lead balls. #4 buckshot is devastating at very close range, but quickly looses its energy. 00 buck is probably a better self-defense load.
|Size||Pellets Per Ounce – Lead||Diameter||Ideal Use|
|000||6||.36″||Deer / Defense|
|00||8||.33″||Deer / Defense|
|1||19||.32″||Deer / Defense|
|2||15||.30″||Deer / Defense|
|3||18||.25″||Deer / Defense|
|4||21||.24″||Deer / Defense|
With buckshot fired from a defense shotgun with cylinder bore choke you can expect the shot pattern to spread out one inch per each yard the shot travels. A hunting shotgun with a tighter choke will hold the pattern together for a longer distance. Buckshot is incredibly effective against unarmored targets at close quarters distance, but it quickly looses its stopping power after approximately 15 to 25 yards, and at that distance the pattern will be spread so much that you can not guarantee that all the pellets will hit the intended target and not hit an innocent.
12 gauge, 2 ¾” 00 buckshot is the gold standard in self-defensive shotgun ammunition. It has adequate stopping power within approximately 20 yards and has manageable recoil that still facilitates quick follow-up shots.
Rifled Slug Essentials:
Rifled slugs are 1 ounce to 1 ¼ ounce lead projectiles that are spin stabilized like a bullet. Rifle and handgun bullets are smooth, but they are fired through rifled barrels which adds in-flight spin-stabilization to the projectile to increase accuracy (like when throwing a football). Most shotguns are smoothbore, so to increase accuracy the slugs themselves are rifled so as to spin as they travel down the smooth barrel and on to the target.
The rifled slug enables a smoothbore shotgun to be used as a bullet launcher and allows the shooter to stretch out the effective range and engage targets beyond shot or handgun. The slug can give the shooter impressive penetration through barriers or large mammals where buckshot might not drive deeply enough.
Rifled Slug Range and Accuracy:
Most smoothbore shotguns with a simple bead sight are capable of shooting a fist size group at 100 yards. At 50-yards it is unremarkable to shoot a group that has the giant holes touching. It is important to note that you will have different accuracy results when using different brands of ammunition. One brand may shoot tight groups from one shotgun, but looser groups in another. Test different brands to find which shoots best from your gun.
Whereas buckshot is only effective out to around 45 yards, rifled slugs increase the combat effectiveness of the shotgun out to as far as 125 yards. Beyond that the groups open up to a point where hit probability falls and the projectile starts to drop rapidly.
Inside 125 yards the slug flies an almost perfect match of the .357 Magnum or .44 Magnum pistol trajectory, both of which are considered flat-shooting, long-range handgun rounds. Zeroing the shotgun about an inch and a half high at 50 yards puts the slugs touching either side of the line of sight out to 100 yards.
Most bead-sighted shotguns are likely to have an approximate 100-yard zero, which runs about three to four inches high at the more common 50 to 75-yard distances, leading the unknowing to mistake trajectory for inaccuracy.
Rifled Slug Damage and Devastation:
The combination of huge mass (a 1-oz. slug is approximately 438 grains) and high velocity of the projectile (a respectable neighborhood of 1500-1600 feet per second), along with the fact that most are slugs are expanding, offers the shotgunner tremendous stopping power out to 125 yards. The shotgun slug has low sectional density and a large frontal area, slowing it quickly, but even as it crosses 125 yards, it is still a roughly .70 caliber bullet traveling at .45 ACP muzzle velocity. Even with “Low-Recoil” slugs, with a muzzle velocity of 1200-1350 feet-per-second, penetration at distance is likely to be through and through, especially if a harder slug is selected.
These rounds can be aimed fairly accurately with the bead sight on most shotguns, however when fired from a shotgun equipped with front and rear iron sights or a red-dot sight system, they can be aimed very accurately. Because of the limited distance that buckshot may be employed, many shotgun experts are recommending the strict use of slugs, as they can be used at close range and long distances (relative to shotguns).
The shooter must do the hard work of testing slugs in order to find the magic combination of acceptable recoil, accuracy, and point of impact relative to point of aim. If you are going to be using a semi-automatic shotgun you must do thorough testing of your intended slugs in order to verify reliable cycling. Test fire a batch of several different brands and see which you get the best results from. Then buy as much as you can and practice often.
Shooting Rifled Slugs With Chokes:
A “Cylinder Bore” choke is nothing but a straight barrel with no choke at all. It is safe to shoot rifled slugs out of a cylinder bore choke barrel, however the slug may not grip the inside walls of the barrel enough to create enough spin to appropriately stabilize it.
An “Improved Cylinder” choke will provide the best spin stabilization for rifled slugs fired from a smooth-bore barrel. The choke diameter is large enough to let the slug pass through without damaging the choke, but just snug enough to give the rifled groves on the slug enough to grip and help spin stabilize it.
Several rifled slug manufacturers state that their slugs are safe to shoot through any type of choke, however you can see in the video below that any choke other than “Improved Cylinder” will damage or prematurely wear out the choke. It is best to avoid shooting slugs out of a “Modified Choke”, “Improved Modified”, or a “Full Choke”.
Sabot rounds (pronounced “say bo”) are smooth projectiles that are fired from special shotguns equipped with rifled barrels. The actual projectile is narrower than the barrel, but the projectile has a plastic sleeve around it that grips the groves of the barrel to induce spin, but then separate from the projectile via aerodynamic forces once it has departed the barrel. These rounds are very accurate when employed with a scope equipped shotgun. It is not recommended to shoot buckshot or birdshot out of sabot barrels as they will damage the rifling.
Another option is to use a rifled choke on shotguns that are set up to accept chokes (such as bird hunting shotguns). The barrel is smooth, but just before the sabot exits the shotgun it passes through the choke and receives a stabilizing spin.
2.75″ vs 3″ Shells:
12 gauge ammo is either 2 3/4″ or 3″ long. The longer shells have more pellet and usually more propellant. While a little more powerful than the shorter rounds, their recoil is very abusive. Their slight increase in terminal performance on the target is not worth the recoil and abuse inflicted on the shooter and its negative effect on the ability to rapidly and accurately engage targets. Therefore 2 3/4″ shot shells and slugs are entirely adequate for combat shooting.
High-Brass vs. Low-Brass:
The brass part of a shotgun shell is where the gunpowder is located. Shown right, the shotgun shell shown on the left is referred to as “low-brass” and is usually associated with less powerful bird-shot and blanks. The shotgun shell on the right in the is referred to as “high-brass” and is usually associated with more powerful buckshot, rifled slugs, and sabot rounds (as these rounds require more propellant).
Reduced Recoil Shotshells:
Shotguns can be intimidating to shooters of a smaller stature. This has a negative effect on their ability to effectively use the weapon. Several ammo manufactures have developed “reduced recoil” shotgun ammo for buckshot as well as rifled slugs. This ammo uses slightly less propellant and has significant less recoil, however there is minimal decrease in terminal performance. Low-recoil slugs ten to be one ounce (approximately 438 grains) and depart the muzzle between 1200 and 1300 feet per second. The shotgun slug has low sectional density and large frontal area, slowing quickly, but even as it crosses 125 yards, it is still a roughly .70-caliber bullet traveling at .45 ACP muzzle velocity. Penetration with a low-recoil slug at distance is likely to be through and through, especially if a harder slug is selected. To sum it up: just about all of the kick-ass on the receiving end, with much less abuse to the shooter.
Less Than Lethal / Riot Control: