Law Enforcement Official Protection and Officer John C. Knight Memorial Act of 1999

Law Enforcement Official Protection and Officer John C. Knight Memorial Act of 1999 - Amends the Brady Handgun Violence Prevention Act (Brady Act) to include within the definition of "armor piercing ammunition" a projectile which the Secretary of the Treasury: (1) has determined is substantially similar in design and manufacture to any ammunition designated for use as armor piercing, armor piercing incendiary, or armor piercing tracing by any military or law enforcement authority of the United States; or (2) finds is capable of penetrating the Executive Protection Exemplar (defined as the minimum level of protective material that the Secretary determines is essential to the effective protection of law enforcement personnel and their public safety mission).

Directs the Secretary to promulgate standards for the uniform testing of projectiles against the Executive Protection Exemplar which shall take into account the effective range of firearms from which the projectile may be fired and the nature of the propellants available for use.

(Sec. 4) Amends the Internal Revenue Code to define "firearm," for purposes of provisions regarding excise taxes, to include: (1) any laser sight suitable for use as a sight for any firearm; and (2) any firearm on which a laser sight is permanently mounted.

(Sec. 5) Amends the Brady Act to include within the definition of "armor piercing ammunition" a projectile that may be used in a handgun that the Secretary determines to be capable of penetrating body armor.

Directs the Secretary to promulgate standards for the uniform testing of projectiles against the Body Armor Exemplar (defined as body armor that the Secretary determines meets minimum standards for protection of law enforcement officers), based on standards developed in cooperation with the Attorney General, taking into account variations in performance that are related to the length of the barrel of the handgun from which the projectile is fired and the amount and kind of powder used to propel the projectile.