SAAMI
Also: Sporting Arms and Ammunition Manufacturers' Institute
The US industry body that publishes voluntary standards for cartridge dimensions, chamber drawings, and maximum pressures.
SAAMI, the Sporting Arms and Ammunition Manufacturers’ Institute, is the American organization that develops and publishes voluntary standards so that ammunition and firearms from different makers work together safely. Its specifications define the external dimensions of a cartridge, the matching chamber drawing, and the headspace tolerances that keep a given round interchangeable across rifles. A cartridge that has been standardized by SAAMI is no longer a wildcat.
Most relevant to load safety, SAAMI assigns a maximum average chamber pressure to each standardized cartridge, the ceiling that published load data is built to respect. The European counterpart, the C.I.P., performs a similar role with somewhat different testing methods, which is why pressure and dimension figures for the same cartridge can differ slightly between the two systems.