Zündhütchen

Zündhütchen is the German term for a firearm primer, the small explosive charge that ignites the propellant in a cartridge. In most modern firearms, the primer is a metal cup seated in a dedicated primer pocket in the cartridge case. When struck by the firing pin, the primer detonates and creates a flame that ignites the main powder charge. Primers are used in centerfire cartridges, and rimfire designs incorporate the priming compound in the rim of the case rather than in a separate cup.

Primers come in two pocket designs. Boxer primers have the anvil integral to the primer itself, and use a single flash hole in the cartridge case. Berdan primers have the anvil in the cartridge case and use two flash holes. The primer compound inside is a sensitive explosive, typically lead styphnate-based formulations, sometimes with stabilizers and secondary compounds.

Rimfire cartridges place the priming mixture in the rim of the case, rather than in a separate cup, and are generally cheaper and less reloadable than centerfire cartridges. Centerfire primers are designed for standardized pockets in cases; reloading uses specific primer types and sizes.

History and safety: Zündhütchen were developed in the 19th century as metallic cartridges were introduced, replacing earlier percussion-based ignition systems. Modern primers continue to be subject to strict handling and storage requirements; exposure to the components can pose health risks. Lead-free primers have been developed and are used in some applications, but availability and reliability vary.