“Armor piercing variants of the 5.7x28mm are only offered to law enforcement and military customers. Commercially available variants of the 5.7x28mm cartridge are classified by the U.S. Bureau of Alcohol, Tobacco, Firearms and Explosives (ATF) as being not armor piercing and it was claimed that the SS192 and SS196 cartridge variants did not penetrate Kevlar vests in tests conducted by FNH USA.”
I thought police and soldiers just used ball ammo/FMJ.