Examples of Boxer primers
The pictures below are of large Boxer primers and are shown about 4 times actual size. Primers come in two sizes, small, for up to about .35 calibre and large for anything bigger. They also come in separate types suitable for rifle and in a less energetic form for pistol cartridges. In Berdan primers, the anvil is in the cartridge case, so the primer is a simpler construction, basically just a cup containing the explosive compound: see Cartridge components.