Penal Code § 16660

As used in this part, “handgun ammunition designed primarily to penetrate metal or armor” means any ammunition, except a shotgun shell or ammunition primarily designed for use in a rifle, that is designed primarily to penetrate a body vest or body shield, and has either of the following characteristics:

(a) Has projectile or projectile core constructed entirely, excluding the presence of traces of other substances, from one or a combination of tungsten alloys, steel, iron, brass, beryllium copper, or depleted uranium, or any equivalent material of similar density or hardness.

(b) Is primarily manufactured or designed, by virtue of its shape, cross-sectional density, or any coating applied thereto, including, but not limited to, ammunition commonly known as “KTW ammunition,” to breach or penetrate a body vest or body shield when fired from a pistol, revolver, or other firearm capable of being concealed upon the person.