SAAMI Publishes the First Public Standard for a 5.56 Cartridge

The Sporting Arms and Ammunition Manufacturers' Institute, which writes the voluntary safety standards most American guns and ammunition are built to, has accepted a new rifle cartridge for standardization: the 5.56 Commercial, abbreviated 5.56 COMM. SAAMI announced it on October 12. Hornady introduced the cartridge, with a 55-grain bullet at 3,400 feet per second and a maximum average pressure of 62,000 psi.

It fills an odd gap. Millions of rifles are marked 5.56 or 5.56 NATO, but there has never been a publicly available standard for 5.56x45, as SAAMI itself notes. SAAMI's own .223 Remington standard is lower pressure, which is why the long-standing advice against firing 5.56 ammunition in rifles chambered only for .223 still applies.

SAAMI is careful about what the new standard does not do. It does not imply conformance with any military or NATO specification, and because there is no public standard for 5.56x45 or 5.56 NATO, the institute says blanket statements about compatibility between those products and 5.56 COMM are impossible. The standard is voluntary: gunmakers do not have to roll-mark rifles 5.56 COMM and ammunition makers do not have to use the headstamp, though both are acceptable.

If you have a rifle marked anything other than 5.56 COMM and want to shoot ammunition made to the new standard, or the reverse, SAAMI's advice is to ask the firearm or ammunition manufacturer first.