Chamber (firearms)

The chamber of a firearm is the portion of the barrel (or separate component directly associated with the barrel) that is specifically designed to hold the cartridge or shotshell before firing. It is a critical component in the firing sequence, providing a sealed or near-sealed environment for the cartridge to properly ignite and propel a projectile.

The chamber's dimensions are precisely engineered to match the specific cartridge it is intended to hold. This close fit ensures proper alignment of the cartridge with the bore of the barrel and prevents excessive gas leakage during firing. A mismatch between the chamber and the cartridge can lead to malfunctions, damage to the firearm, or even dangerous overpressure situations.

Chambers can be integral to the barrel itself, or a separate piece that is securely attached. Revolvers typically have multiple chambers located within a rotating cylinder. The design and materials used in chamber construction are crucial for withstanding the high pressures generated during firing.

Key characteristics of a chamber include:

• Size and Shape: Must precisely match the cartridge dimensions.
• Strength: Must withstand high pressures without deformation or failure.
• Alignment: Must align the cartridge with the bore for accurate projectile trajectory.
• Surface Finish: Smooth interior finish to facilitate cartridge loading and extraction.
• Headspace: Refers to the distance between the breech face (or bolt face) and a specific point on the cartridge case (e.g., the shoulder in a bottleneck cartridge). Proper headspace is vital for safe and reliable function.

The term "chambering" is sometimes used to describe the caliber or cartridge that a particular firearm is designed to use (e.g., a rifle "chambered in .308 Winchester"). Improper chambering can result in a catastrophic failure of the firearm and serious injury to the user.