Jerry White
New member
During the 1970s, NATO members signed an agreement to select a second, smaller caliber cartridge to replace the 7.62 mm NATO. Of the cartridges tendered, the 5.56 mm was successful, but not the 5.56 mm loading (3.56 g (55 gr), M193 Ball) as used by the U.S. at that time. Instead, the Belgian FN SS109 loading was chosen for standardization. The SS109 used a 4 g heavier (62 gr) bullet with a steel core inserted, fired at a lower muzzle velocity for better long-range performance, specifically to meet a requirement that the bullet be able to penetrate through one side of a steel helmet at 600 m. It did so.
Jerryboy
Jerryboy