Abstract: A projectile suitable for firing from a gun barrel contains an additive which is dispensed along the gun barrel by the pressure of a gas propellant so as to reduce barrel wear. A charge of additive (11) is stored within a cylindrical recess in the rear face (12) of the projectile. In use, the pressure of the gas propellant acts on a nylon piston (6) slidably located within the tube (2), which piston in turn pressurizes the charge (11) forcing it forward through the four extrusion ports (9) to the exterior of the projectile. The charge additive (11) is preferably a mixture of a thermal insulator and a lubricant, best characterized by silicone oil or a paste mixture of titanium dioxide and silicone grease. The invention is particularly applicable to small arms bullets for firing from a rifled gun barrel, and may be incorporated in existing hollowed bullets, for example tracer bullets.