A liquid spray gun nozzle assembly is disclosed comprising a coating liquid inlet portion comprising a liquid connector for connection to an external liquid source; a coating liquid outlet portion comprising a liquid nozzle for spraying a coating liquid fed into the nozzle assembly through the coating liquid inlet portion, the liquid nozzle being disposed along a spray axis; a coating liquid flow path fluidly connecting the coating liquid inlet portion to the liquid nozzle; and a spray gun connection portion opposite the coating liquid outlet portion adapted to connect the liquid spray gun nozzle assembly to a compatible liquid spray gun body. The spray gun connection portion comprises a nozzle assembly sealing surface adapted to seal the liquid spray gun nozzle assembly to the compatible liquid spray gun body, the nozzle assembly sealing surface comprising first and second sealing members that are each circular and concentric with one another.