Reference Guides
100 plain-English guides spanning terminology, ballistics, specifications, safety, and regulation.
Glossary
Ballistics, safety, and caliber terms defined clearly and tied to named authorities.
Specifications
How firearm measurements, tolerances, and performance figures are defined and compared.
Historical Profiles
How firearm mechanisms, ammunition, and manufacturing methods developed over time.
Firearm Data Index is an independent, plain-English reference library dedicated to making technical firearm information accurate, accessible, and verifiable. Every entry translates dense engineering standards, ballistics science, and federal regulatory frameworks into clear explanations any researcher can understand and trust.
Each topic is written as objective educational reference material and tied to a named public authority — standards bodies such as SAAMI and NIST, and government sources such as the ATF, the FBI, and the Government Publishing Office — so any statement can be traced back to its origin rather than taken on faith.
Begin with the reference guides, review defined terms in the glossary, or study measurements in the specifications index.