Rimfire Anatomy

Sellier & Bellot rimfire ammunition combines technological advancement with strict testing and quality control to build the best rimfire ammunition made.  Our rimfire ammunition is carefully assembled using the best brass cases with proven primer compound combined with the finest, most sought after powder and bullet designs in the industry.  That’s why hunters and shooters from around the world pursue their passion with the unmatched quality of Sellier & Bellot rimfire ammunition.

A loaded rimfire cartridge consists of a case (usually brass) with integrated primer compound inside the rim, a projectile (bullet), powder and a primer. Most experts agree that the .22 Long Rifle is the most common cartridge in the world.
Rimfire Cartridge Case: The rim of a rimfire case contains the priming compound, while the cartridge case itself contains the projectile and the powder. Once the rim of the rimfire cartridge has been struck by the firing pin and the bullet is discharged, the rimfire cartridge cannot be reloaded because the head has been deformed.

Projectile: This component of the loaded round of ammunition is usually called the bullet. It is usually referenced by diameter (such as .22”), the grain weight of the bullet (50 grains), and the bullet style (hollow point, full metal jacket, etc.). A bullet is generally made of lead alloy with or without a jacket made of a copper alloy.

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 bullet 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. Rimfire cartridges were originally designed to be loaded with the easily ignited black powder. Today rimfire cartridges consume unique smokeless powders that are easily ignited and burn progressively. Due to the smaller case capacity, dense smokeless powder with a ball or small flake design are used in rimfire cartridges.

Primer: As noted above, rimfire cases have the priming compound inserted around the inside of the case rim at the base. Unlike centerfire primers, there is no anvil to act as a friction agent so most rimfire priming compound requires the addition of ground glass to assist in the ignition.  The firing pin strikes the case rim and ignites the sensitive priming mixture causing a flame to be generated. Note: There is no flash hole to focus the ignition gases into the center of the powder charge.

When a rimfire firearm is fired, the rim located on the side of the case is crushed, which ignites the priming compound. This produces a flame that ignites the powder. The quickly burning powder then creates large amounts of gas that expand the case to seal the chamber and pushes the bullet down the barrel. The now empty brass case is then removed by the action of the firearm or manually in the case of a revolver.

NOTE: Rimfire bullets may perform differently in different rimfires. What shoots well in your rimfire may not be the best choice for another rimfire of the same make and model. To maximize the full potential of your rimfire, try various Sellier & Bellot rimfire bullet styles and weights to determine which round performs best in your rimfire. 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 caliber for the firearm by matching the caliber markings on your firearm with those on the ammunition head stamp.