A pigging ball valve with a housing and ball core supported for rotation within the housing. The ball core sits on a valve seat, which is supported by a seat carrier. The valve seat carrier has three distinct diameters that locate the seat in the housing and thus provides an anti-cocking feature. A seat insert has a pressure sealing surface and wiper lip on the outer diameter of the pressure sealing surface. An internal seat deflector ring is provided inside of the pressure sealing surface. The seat carrier is spring loaded.