An extrusion die is provided with an adjustable end seal assembly. The extrusion die includes a die body, and the adjustable end seal assembly includes an end seal device and a wedge mechanism. The adjustable end seal assembly has an engaged configuration and a disengaged configuration. When in the engaged configuration, the adjustable end seal assembly is held forcibly against the die body. When in the disengaged configuration, the adjustable end seal assembly is either spaced apart from the die body or held against the die body with less force than when in the engaged configuration. Methods of operating such an extrusion die are also provided.