5.7x28 mm FN Cartridge Standardized By SAAMI

The 5.7x28 mm FN centerfire pistol and revolver cartridge has been accepted by the Sporting Arms and Ammunition Manufacturers’ Institute (SAAMI). Its standard specifications were published in late August. FN Herstal, S.A., designed it, and the proposal for standardization came from SAAMI voting member Fiocchi of America, in partnership with FN America.

It features a 40-grain bullet traveling at a velocity of 1,750 f.p.s. from a 5" test barrel at a maximum average pressure of 48,500 p.s.i. Full specifications, including mechanical drawings, are found on SAAMI’s technical drawing page.

Design of the 5.7x28 mm FN began at FN Herstal, S.A., in the 1980s, when the North Atlantic Treaty Organization (NATO) was in search of pistol ammunition with better performance than the 9 mm NATO. An application for the new cartridge was filed with the U.S. Patent Office in 1989 and the first load was revealed to the public in 1990. The earliest firearms to chamber it were FN’s FN P90 and FiveseveN. Today, guns in the chambering are offered by nearly every major manufacturer. 

NATO standardized the cartridge in 2021, integrating it into its Multi-Caliber Manual Of Proof and Inspection list. It joined 9 mm NATO, 5.56 mm NATO, 7.62 mm NATO and 12.7x99 mm NATO (more widely known as the .50 BMG).

FN Herstal has developed several of the world’s most popular cartridges. The 5.56 NATO and 7.62 NATO—standardized by NATO in 1957 and 1981, respectively—were company designs. Acceptance by SAAMI underscores the firm’s dedication to providing law-abiding citizens, armed forces and security forces with high-performance and efficient small-caliber ammunition.

SAAMI was founded in 1926 at the request of the Federal government. The organization is the leader in promoting firearm safety by creating standards that ensure safety, reliability and interchangeability of ammunition, components and firearms.