It's obvious that Dana Milbank does not understand at least one thing about firearms: Specifically what constitutes an armor piercing bullet in regard to bullet proof vests.
Bullet proof vests are just that for nearly all handgun fired bullets. These bullets are propelled with gun powder charges that are smaller than those typically used in rifles (except the .22 caliber, rim fired), and the bullet noses are rounded rather than pointed as are most bullets used for hunting.
Center fired rifles, those where the primer is centered in the end of the casing, generally use larger casings allowing greater powder charges that propel a pointed bullet at velocities significantly greater than bullets fired from handguns. The pointed bullets and the greater velocities enable a typical hunting bullet to pierce bullet proof vests. Gun control advocates use this fact in an attempt to label typical hunting cartridges as "armor piercing". It's a prime example of cherry picking information.