https://cartridgeatlas.com/en/notes/A few distinctions make an ammunition reference much easier to read.enThu, 29 Oct 2026 00:00:00 GMThttps://cartridgeatlas.com/en/notes/#note-1https://cartridgeatlas.com/en/notes/#note-1Thu, 29 Oct 2026 00:00:00 GMTCaliber describes a bore or projectile designation. A cartridge name identifies a particular ammunition design. Similar numbers do not establish that two cartridges are the same.https://cartridgeatlas.com/en/notes/#note-2https://cartridgeatlas.com/en/notes/#note-2Thu, 29 Oct 2026 00:00:00 GMTThese names describe ignition systems. Rimfire priming is contained within the rim; a centerfire cartridge uses a primer located centrally in the case head.https://cartridgeatlas.com/en/notes/#note-3https://cartridgeatlas.com/en/notes/#note-3Thu, 29 Oct 2026 00:00:00 GMTStandards describe dimensions, limits and test procedures. Bullet mass and published velocity belong to a specific factory product and its test conditions.https://cartridgeatlas.com/en/notes/#note-4https://cartridgeatlas.com/en/notes/#note-4Thu, 29 Oct 2026 00:00:00 GMTThe abbreviation gr means grain, a unit of mass. One grain equals 0.06479891 grams. Keep units visible when comparing specifications.https://cartridgeatlas.com/en/notes/#note-5https://cartridgeatlas.com/en/notes/#note-5Thu, 29 Oct 2026 00:00:00 GMT12 gauge identifies a shotgun bore category. A complete shotshell designation also includes case length. The length refers to the opened case, not simply the closed cartridge.https://cartridgeatlas.com/en/notes/#note-6https://cartridgeatlas.com/en/notes/#note-6Thu, 29 Oct 2026 00:00:00 GMTStart with official standards and manufacturer documentation. Historical catalogues establish what was offered at a particular time, not what is still in production.