Fortified doors are designed to withstand various levels of force and impact, depending on their construction and purpose. The type of bullet a fortified door can stop will largely depend on the materials used in its construction and the level of reinforcement.
For example, a heavily fortified door made of steel or reinforced with steel plates can potentially stop handgun bullets such as 9mm, .40 S&W, or .45 ACP. However, it may not be as effective against higher caliber rounds like .357 Magnum or .44 Magnum.
For protection against higher caliber bullets or even rifle rounds, specialized armored doors with thicker and stronger materials such as ballistic steel or bullet-resistant glass may ...