Ammunition Law and Legal Definition
Ammunition is defined by federal law as cartridge cases, primers, bullets, or propellent powder designed for use in any firearm. Federal law prohibits manufacturing and selling "armor piercing ammunition".
"Armor piercing ammunition" is defined in federal law [18 U.S.C. 921(17)(B)] as "a projectile or projectile core which may be used in a handgun and which is constructed" of various metals harder than lead, or "a full jacketed projectile larger than .22 caliber designed and intended for use in a handgun and whose jacket has a weight of more than 25 percent of the total weight of the projectile."