Shotshell Anatomy

Sellier & Bellot shotshell ammunition combines technological advancement with strict testing and quality control to build the best shotshell ammunition made.  There’s really not much need to reload for performance since our shotshell ammunition is carefully assembled using the best primers, powders and hulls combined with the finest, most sought after shot, slug and buckshot configurations in the industry.  That’s why sport shooters, hunters and law enforcement officers from around the world depend on the unmatched quality of Sellier & Bellot shotshell ammunition.

Click a thumbnail below to view the Sellier & Bellot shotshell anatomy.

A loaded centerfire shotshell cartridge consists of a case or hull (paper or plastic tube and usually a brass head), a projectile (various shot sizes or slugs), a wad, powder and a primer. The crimp is the portion of a cartridge case that is bent inward to hold the shot in place.

Shotshell Cartridge Case or Hull: The shotshell case (hull) has a head on one end that houses the primer and seals the back of the chamber. The flash hole is the hole connecting the primer pocket to the inside of the case. Besides sealing the back of the chamber, the head of the case is used to extract the case from the chamber. The inside of the case will be of uniform thickness and in most cases there is a integrated base wad formed at the base of the head.  Most shotshells are available in 10, 12, 16, 20, and 28 gauge, plus .410 bore. Gauge is a unit of measurement of a shotgun bore. It is derived from the number of round lead balls of the same diameter that weigh one pound. As an example, a lead ball the same diameter as a 12 gauge bore is 1/12th of a pound. The .410 is the only exception-measured in the diameter of the projectile. Within their respective gauge designations, shotshells are available in different lengths. Common lengths are 2 ¾ inch, 3 inch and 3 ½ inch. The longer the shell, the greater the amount of shot that it delivers.

Projectile (shot or slug): Bird Shot or Target Shot is most commonly available in lead or steel, and it is manufactured in various sizes (smaller size #9 .08” diameter up to larger size T .20” diameter) suited for different types of sport shooting and hunting. Non toxic shot is usually defined by shotshell pellets made from steel and other materials approved by the USFWS for hunting waterfowl. Buckshot is most commonly available in lead or rubber, and it is manufactured in larger sized pellets (smaller size #4 Buck .24 diameter up to larger 000 Buck .36 diameter) suited for close up varmint (coyote) and deer hunting in tight quarters. Shot size is a numerical (or sometimes letter) designation for the average diameter of pellet. The number is determined using the formula (17-number designation)/100. For example, #2 shot is .15 inches (17-2)/100. In some instances, the addition of granulated plastic buffer is added to prevent pellet deformation and produce tighter, more uniform patterns. Rifled and saboted slugs are primarily designed for hunting in areas of close range where rifles are not permitted. Slugs and buckshot are also popularly used in many law enforcement situations.  Sabot is a term derived from the French word for shoe. Sabot slugs are generally defined as a plastic sleeve that encases a smaller bullet, enabling the projectile to be fired from a larger bore firearm.

Wad or Shot Cup: A wad varies in design dependent upon the shotshells intended use. The wad or shot cup is usually constructed of plastic and it has several purposes such as to separate powder from projectile (shot/slug), to seal propellant gases behind the shot/slug, to hold shot/slug together in the barrel and to maximize the shot pattern or slug accuracy.
Powder: The general term for any chemical compound or mixture used in firearms that burns upon ignition. The gases produced by this rapid combustion propel the shot charge or slug down the bore. One major type is black powder, which is a mixture of charcoal, sulfur and potassium nitrate (saltpetre). It's used in older cartridges. Another major type is smokeless powder, which is principally used in modern ammunition. It's a granular nitrated chemical compound made with either a nitrocellulose base or a combination of nitrocellulose and nitroglycerin. Smokeless powder and black powder are the two basic forms of gunpowder. Dram Equivalent is a measurement to compare the velocities in modern smokeless shotshells. It is derived from the measurements used in blackpowder where a dram is a measurement of volume of powder in the charge.

Primer: The most common shotshell primer is designated #209 and these are used for all shotshell gauges. The #209 primer is commonly referred to “battery-cup” style primer and the #209 design is two-part (the anvil and primer cup are supported in an external cup). The #209 primer is a round device that is placed in the center of the “head” area of the shotshell case. This little device has a cup, which holds the priming compound, and an anvil. The anvil rests lightly on the priming pellet, which is crushed between the dent made by the impact of the firing pin and the anvil to initiate ignition. The firing pin strikes the primer and ignites the sensitive priming mixture causing a flame to be generated. Shotshell primers are not interchangeable with metallic centerfire primers. To help reduce confusion, the #209 primer is larger and shaped differently than metallic primers.

When a firearm is fired, the firing pin indents the primer, which ignites the priming compound. This sends a flame through the flash hole of the shotshell brass head, which ignites the powder. The quickly burning powder then creates large amounts of gas that expand the case to seal the chamber and pushes the shot charge or slug down the barrel. The now empty shotshell case is then removed by the action of the firearm. The level of constriction in the shotgun’s muzzle is defined as “choke”, and the choke affects how wide the shot pattern spreads out after it leaves the barrel.  The choke selection also affects the accuracy of slugs so choose carefully to maximize the effectiveness of your shotgun.

NOTE: Shotshells may perform differently in different shotguns. What shoots well in your shotgun may not be the best choice for another shotgun of the same make and model. To maximize the full potential of your shotgun, it is important to know where your shotgun shoots and how it patterns with the various Sellier & Bellot shotshell load offerings to determine which round performs best in your shotgun. To become a more successful shooter, spend some time at your local gun range before and after hunting season to practice proper shooting techniques and develop a complete understanding of how your firearm and ammunition combination will perform in the field. 

SAFETY: Make sure that you double check that your ammunition is the appropriate gauge or caliber for the firearm by matching the gauge or caliber markings on your firearm with those on the ammunition head stamp. Remember, your shotgun chamber must be able to accept the length of shell you wish to shoot. 3 inch or 3 ½ inch shells cannot be safely used in guns with 2 ¾ inch chambers. However, 2 ¾ inch shells can be used in guns with 3 inch or 3 ½ inch chambers.