5.7x28mm is included in the latest standardisation agreement from NATO.
NATO has recognised the FN Herstal-designed 5.7x28mm calibre as a new standard after issuing STANAG 4509.
FN Herstal stated on 25 February that the Belgian Army is now supporting efforts for the P90 submachine gun (pictured) and the Five-seveN pistol to become the first NATO 5.7x28mm calibre weapons.
STANAG 4509 guarantees interchangeability between handgun and submachine gun ammunition from different manufacturers, in line with Land Combat Group Dismounted Soldier System requirements from NATO.
The 5.7x28mm calibre is integrated into the Multi-Caliber Manual Of Proof and Inspection (AEP-97) and joins the standardised NATO small-calibre ammunition portfolio, which includes the 9x19mm, 5.56x45mm, 7.62x51mm and the 12.7x99mm (.50) calibres.