Thermal spray gun (1) and/or nozzle (120) includes a nozzle body and a liner material (123) arranged within the nozzle body. A material of the nozzle body has a lower melting temperature than that of the liner material (123). A wall thickness (C) of the liner material (123) has a value determined in relation to or that corresponds to a wall thickness (D) of the nozzle body. Alternatively or additionally, a ratio of a total wall thickness of a portion of a nozzle (120) to that of a wall thickness (C) of the liner material (123) has a value determined in relation to or that corresponds to the wall thickness (C) of liner material (123).