Ins and Outs of Shotgun Loads Explained

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By Bryan Lynch •  14 min read

For many, the language and meaning surrounding shotgun shells are almost like a secret code. For those coming from a rifle or pistol background where calibers and grain weights are the common measurements, dealing with gauges, grams, ounces, and shotshell lengths seems foreign.

Understanding how these different terms work together to provide information about shotgun shells and how they are used is essential for anyone interested in hunting or competitive shotgun shooting.

Shotgun shells, or shotshells, are ammunition used in smooth-bore shotguns.

Shotgun shells are typically made of paper or plastic with a rimmed brass base that holds the primer. The cylindrical cartridge encloses a wad or sabot, the powder, and the projectiles. In most cases, the projectiles are round lead or steel shot. Some specialized shotgun shells may shoot large single projectiles called slugs or other specialized types of loads.

Hunting with shotguns is a popular pastime. Shotguns are best known as bird-hunting firearms used for upland game birds and waterfowl.

Many states have now banned the use of high power large caliber rifles for hunting many game animals in favor of shotguns. Whatever your use of a shotgun for hunting, it is important to understand shotgun loads and how to choose the most effective shotgun shells.

Where to Start To Understand Shotgun Shells?

The most obvious place to start is with the standard shotgun gauges. Rifle and pistol shooters are familiar with ammunition that is described by caliber. Rifle and pistol ammunition is designated by the nominal measure of the internal diameter of the gun barrel.

For example, a .45 caliber pistol cartridge is designed to fire a bullet that is .45 inches in diameter. A rifle designed to shoot cartridges that are identified as 5.56 NATO is measured in millimeters. Consequently, the bore of the barrel of a rifle for these cartridges is typically 5.56 millimeters in diameter.

What is Shotgun Gauge?

On the other hand, shotguns are designated by the gauge of the barrel. Shotgun gauges are an old standard that is relatively complicated to understand.

In simple terms, the gauge of a shotgun is determined by the weight of a solid ball of lead that will fit the internal diameter of the shotgun barrel. At one time, lead balls were a common means of measuring sizes and weights.

One-Twelfth of a Pound Lead Balls

In the case of a 12-gauge shotgun, a sphere of lead that will fit into the barrel measures 1/12th of a pound. It takes 12 lead balls of this size to make one pound. Consequently, the shotgun gauge is designated as a 12-gauge. This measurement technique dates back to the way cannons were designated. An eight-pound cannon would fire an eight-pound round ball.

Measuring shotguns by gauge rather than caliber continues to be the standard.

Twelve Gauge – The Most Popular Shotgun Bore Diameter

The twelve-gauge bore-diameter shotgun is undoubtedly the most popular shotgun used in the U.S. There are more 12 gauge shotguns and shotgun shells sold in the U.S. than all the other shotguns gauges combined.

For the rest of this article, I will concentrate on 12-gauge shotguns and shotshells. The other gauges of shotguns and shotgun shells are similar but vary in size, which can make some difference in performance.

The Anatomy of Standard 12-gauge Shotgun Shells Explained

In essence, a shotshell cartridge is like any other ammunition for any other firearm. Some common characteristics are shared by rifle, pistol, and shotgun shells. However, shotgun shells do have some particular differences that should be known and understood.

All ammunition requires a container to hold the components, powder to propel the projectile, a bullet, and an ignition source. In the case of a rifle or pistol, these components are known as the cartridge case, the powder, the bullet, and the primer.

A shotshell contains a primer and powder, but instead of a bullet, most shotgun shells contain several smaller projectiles called shot or shot pellets. Many shotshells also have a shot wad that separates the shot from the powder charge, which helps keep the shot load together as it moves down the barrel.

Instead of the brass cartridge case common to rifle and pistol ammunition, shotshells typically have a brass base that holds the primer. The upper portion of the shotshell is made of plastic or paper that is crimped at the top to hold the components securely.

Shotgun Shells – Length is Important

In addition to the internal components, 12 gauge shotgun shells come in several lengths.

Standard modern shotgun shell lengths include 2 1/2 inch, 2 3/4 inch, 3 inch, and 3 1/2 inch lengths.

When you purchase shotgun shells for your shotgun, it is important to know the shotgun shell sizes your gun will safely shoot. Shotgun barrels come with different shotgun chamber depths. This information should be clearly marked on the shotgun barrel.

Longer shotgun shells typically hold more powder and more shot, so the performance is expected to be better. However, you cannot – and should not – try to shoot a shotgun shell longer than the specified shotgun chamber design. At the best, your shotgun will not operate. At worst, your shotgun may suffer a catastrophic failure that can lead to serious injury.

Shot Size – The Critical Factor

One of the first things anyone notices is how shotshells are labeled and marked. A typical box of 12-gauge shotgun shells has various numbers and labels indicating the gauge of the shotshell, the length, and the size of the shot in the shells. Understanding the nomenclature is critical in choosing the right shotgun shells for your hunt or target shooting activities.

This example is typical of the information label on almost every shotshell box. From this, you can glean all the information you need to make the proper shotshell selection from the vast number of variations available on the market.


Every box of shotshells will clearly indicate the gauge. In this case, the gauge is 12, and this ammunition is meant for a 12-gauge shotgun. Modern shot shells come in 10-, 12-, 16-, 20-, 28-gauge, and .420 bore diameter. You must purchase that shotshell gauge for which your shotgun is chambered.

Length Measurement

All shotguns have specific length chamber measurements. Shotgun barrels are designed and built to use only those lengths of shotshells marked on the barrel. If your shotgun barrel is marked 12-2 3/4, you can safely fire 12-gauge shotshells of either 2 1/2 or 2 3/4 inches in length.

Never try to fire a shell length longer than the designated length of the chamber of your shotgun.

Dram Equivalent/Muzzle Velocity

Some shotshell manufacturers still list the dram equivalent on the box label. This is an antiquated measurement that was once used to specify the muzzle velocity of the shotshells. Most modern manufacturers list the average muzzle velocity instead of the dram equivalent.

This number can be misleading as the same shotshell fired in shotguns with different barrel lengths can yield different muzzle velocities.

Shot Weight

The weight listed on the shotshell box label represents how much shot is loaded in each shell in ounces. Modern 12-gauge shotgun shells typically contain from 7/8 of an ounce of shot to 2 ounces or more, especially in specialty loads. In general, the heavier the shot load in the shotshell, the more felt recoil. Shot weight is a good indicator of “knockdown power” and should be considered based on the type of game you are hunting.

Shot Size

The size of the shot loaded into the shotshell is measured by a number. Generally, the smallest shot size you can find is 9. These are very tiny shot that is designed for small game at close ranges. Typically, number 9 shot is used for sporting clays since the very lightweight, small shot is enough to break a clay pigeon, and the larger number of smaller pellets in each shell helps the chances of scoring a hit.

Shotgun ammunition shot sizes

Larger shot sizes may be designated as BB shot or buckshot. The most popular of these loads are designated as 00 buck (or double ought buckshot shells.) These larger pellets are available in most common shotgun gauges and are useful when hunting game such as deer.

Some states mandate shotguns for all deer hunting and may even specify only a certain size of shot or the use of a slug.

Specialty Shotshell Loads

There are a variety of specialized loads for shotguns in various gauges. These specialty loads range from what are considered non-lethal projectiles to highly specialized military and law-enforcement loads that are not available for civilian shooters.

These are some of the specialty loads that may be available on the civilian market:

Rubber Buckshot

Generally, rubber buckshot is a law enforcement tool used for crowd control. This is officially considered a non-lethal round but has been known to cause fatal injuries when used incorrectly. The shotshell is loaded with 00 buckshot-sized rubber projectiles that can cause a painful wound or even break bones in some instances.

Bean Bag Shells

Like rubber buckshot, bean bag shotshells are used as a non-lethal alternative for crowd control or to effectively stop an assailant. This makes bean bag shotshells a popular home or personal defense alternative, where penetration by a standard shotgun shell could pose problems.


The most popular alternative shotgun shell load is the slug.

Slugs are large single shotgun pellets used for hunting game, and typical shotshell pellets aren’t effective. Slugs are measured in the standard shot load sizes of 7/8 ounces, 1 ounce, and 1 1/8 ounce. At short ranges, shotgun slugs are effective and can be equivalent to large-caliber centerfire rifles.

A variant of the slug shotshell is the sabotted slug round. A sabotted shotgun slug is typically smaller in diameter than the bore of the shotgun barrel and is encased in a plastic hull that separates from the slug as it exits the barrel.

This prevents damage to the shotgun barrel and allows shooting slug designs that offer better ballistic coefficients and greater range.

Shotgun ammo

Rifled Slugs

Most shotguns have a smooth barrel bore which does not impart any spin to the shot charge or a slug traveling down the barrel. Any spin on a shot load causes shot dispersion, limiting accuracy and distance.

Rifled shotgun slugs are made with twisted grooves on the slug that impart spin as the slug travels down the barrel to improve stability and accuracy. Most rifled slugs have a concave bottom that puts the center of gravity of the slug toward the nose, further improving performance.

A rifled barrel

Identifying Shot Shells by Color

By convention, shotshells are color coded for easy visual identification. This is not a true standard, but one that most major manufacturers follow. I don’t suggest you depend on the color of a shotshell to represent the gauge accurately. If there is any question, check the gauge printed on the shotshell.

The colors most often associated with a specific shotshell gauge are as follows:


Brown was typically associated with 10-gauge shotgun shells. 10-gauge has fallen out of favor in the U.S. recently and is not seen as much as in years past.

brown shotgun shell

Brown shotgun shells can be found with steel shot, lead shot, or bismuth shot.

Red or Black

Red or Black shell hulls are typically associated with 12-gauge shells. Most manufacturers follow this tradition and continue to manufacture 12-gauge shells with red or black cases.

red shotgun shell


Purple is typically associated with 16-gauge shotshells. This is another shotgun gauge that is becoming harder and harder to find. Many manufacturers who still offer 16-gauge shotshells use almost any color for the shotgun hulls.


If there is any standard that is still much followed in the shotshell industry, it is the color yellow for 20 gauge shotshells. You will be hard-pressed to find a 20-gauge shell that is not yellow. Since the 20-gauge is second in popularity only to the 12-gauge, this is a convenient unofficial standard.

yellow shotgun shell


If you own a 28-gauge shotgun, you are probably familiar with the green color shotgun hulls associated with this shotgun shell gauge. 28-gauge, 16-gauge, and 10-gauge shotguns are becoming rare and aren’t as popular for migratory bird hunting as they once were.

box of shotgun shells

.410 bore Red Shotshells

Most .410 bores shotshells are red. As the smallest of all shotshell sizes, it is not hard to distinguish a .410 from even a 28-gauge shotshell. This means that color is not typically used as an identifier for .410 bore shotshells.

red shotgun shell

Check the Headstamp on the Shotshell

While color can be convenient, it is not really a reliable way to identify shotshell gauges. For many years, stamping the gauge of the shotshell on the brass base of the shotshell has been standard practice.

I suggest that if there is any question about the gauge of a shotshell, you visually check the headstamps for confirmation.

shotgun shell sizes

What Shotgun Shell Should I Use?

Picking the proper length and shot load depends a lot on what you are going to hunt or shoot with your shotgun. A shotgun shell can be configured for almost any purpose, from target shooting to hunting. In many cases, muzzle velocity is a critical factor, especially for hunting larger game or waterfowl. A higher muzzle velocity typically means longer effective distances and more delivered energy to your target.

Most shotgun shooters choose a box of shotgun shells based on the type of game they are hunting. Target shooting has different criteria and needs different considerations for the shot pattern. Target loads are typically higher loads with smaller shot sizes and a larger number of shot pellets per cartridge. Here are my recommendations for choosing the proper shot sizes for different applications:

Target Shooting

There are three basic types of shotgun target shooting, skeet shooting, sporting clays, and trap. All of these types of target shooting require target loads that usually use #9 or #8 shot.

Skeet shooting is usually done at close range, and the clay targets tend to be more fragile, so lighter and smaller shot size works.

Sporting clay competition and trap use heavier targets that need a bit more energy to break. Many shooters in these competitions routinely use #6, #7-1/2, and #8 shot size loads. Some more experienced shooters may opt for lighter loads.


Choosing a shot size for hunting is entirely dependent on your quarry. The following list breaks down my suggestions for shot sizes for some of the most common game animals hunted with a shotgun in the U.S.

Upland Game Bird Hunting

You may be after pheasant, quail, or grouse. In any case, with upland game birds, the best all-around shot size choice is the #6 shot. This size shot provides good distance, maintains a good pattern over distance and is heavy enough to deliver sufficient energy to stop almost any upland game bird you’re hunting.

Waterfowl Hunting

For most waterfowl hunting in the U.S., #5 shot is more than sufficient. #5 shot gives good range and, with the proper choke, delivers a tight, consistent pattern with plenty of take-down power.

For geese or larger waterfowl, I suggest stepping up to #4 or #3 shot. These are higher-flying birds with more mass that need that extra punch.


Turkeys are one of North America’s largest game bird species and require a great deal of skill to hunt successfully. There are several types of shotgun shells made especially for turkey hunting. In general, #4 shot is the smallest shot I would recommend for hunting wild turkeys.

Varmints and Rodents

Shotguns are an excellent means of controlling rodents and varmints in rural areas. There are several types of shotgun ammunition made especially for this purpose.

Birdshot pellets in sizes 7 1/2 to 9 are effective against small rodents such as rats or mice. Larger shot sizes are better suited to controlling skunks and other larger rodents. You may want to consider rifled shotgun barrels for larger varmints such as badgers, coyotes, or raccoons.

Controlled Game Animals

A rifled barrel or rifled slugs are almost a necessity if you are planning on hunting deer or other large game animals found in North America. If you don’t have a rifled barrel, sabot slugs are a good alternative and give almost the same ballistic characteristics.

Don’t expect to find low recoil loads when shopping for a box of shotgun shells loaded with regular or sabot slugs.

In the End, Match Your Shotgun Shell Selection to Your Needs

Once you understand the ins and outs of shotgun shells, choosing the right load for your needs is not as hard as it seems.

Don’t let the different types of shotgun shells overwhelm you. Stick to the basics of your intended uses and the targets you anticipate and apply some common sense, and you will usually make a good decision.

Bryan Lynch

Bryan grew up in the Midwest and spent every waking moment outdoors. Learning how to hunt, fish, read the land, and be self-reliant was part of everyday life. Eventually, he combined his passions for the outdoors, emergency preparedness, and writing. His goal was to spread positive information about this field. In 2019, Bryan authored the book Swiss Army Knife Camping and Outdoor Survival Guide. His second book, Paracord Projects For Camping and Outdoor Survival, is scheduled to be released on March 2, 2021.