The Sporting Arms and Ammunition Manufacturers' Institute (SAAMI) has announced the acceptance of a new rifle cartridge for standardization. The 5.56 Commercial (abbreviated 5.56 COMM) was introduced by Hornady Manufacturing with a 55-grain bullet traveling at a velocity of 3,400 fps. Maximum average pressure is 62,000 psi. The 5.56 COMM cartridge and chamber, as defined here by SAAMI, provides a publicly available consensus standard describing a chamber and ammunition system for commercial practice using the procedures and equipment detailed in the American National Standard SAAMI Z299.4.
"The 5.56 NATO specs of the past presented confusion for many manufacturers over the years. Largely, because there were no publicly available "official" or "standard" specifications like chamber dimensions, cartridge dimensions, chamber pressure and barrel twist and length," Hornady Marketing Communications Manager Seth Swerczek told American Rifleman. "Now, by having the agreed-upon specifications publicly available for all manufacturers, newly produced barrels, rifles and ammo can work in better concert."
Conformance to this specification does not imply or ensure conformance with any military or NATO specification. The absence of publicly available standards for 5.56x45 mm, including variants such as 5.56 NATO, makes blanket compatibility statements of those products to products manufactured to this new standard impossible. The 5.56 COMM specification is a commercial SAAMI standard and will be revised only through the defined SAAMI consensus-based standards development and maintenance processes.
As a voluntary standard, the existence of this specification does not require firearm manufacturers to mark firearms as 5.56 Commercial (or 5.56 COMM). Nor does it require ammunition manufacturers to adopt a 5.56 Commercial (or 5.56 COMM) headstamp, although the use of this designation as a roll mark or headstamp is acceptable practice.
For specific questions on the compatibility of ammunition made to this specification in firearms carrying a roll mark other than 5.56 Commercial (or 5.56 COMM), or vice versa, contact the manufacturer of your firearm or ammunition.
Existing guidance that only .223 Rem. ammunition is to be used in a firearm chambered and roll marked as only “223 Remington” remains unchanged. The use of any 5.56 ammunition, including all military variants as well as ammunition produced to this standard, in a .223 Remington chamber creates increased pressure and is considered an unsafe combination.
The standardization of cartridge and chamber designs, along with pressure standards, a key SAAMI objective in ensuring the safety and interchangeability of ammunition, firearms and suppressors. Its standards provide manufacturers with appropriate guidelines to ensure proper and safe operation and interaction of their products for shooting sports enthusiasts.
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