Copper slug is primarily used in pyrotechnic compositions as a fuel and colorant. It plays a key role in producing blue-green flames in fireworks and signal flares due to its emission spectrum when burned. The slug form allows for controlled burn rates compared to powdered copper, making it suitable for specialized pyrotechnic effects where timing and consistency are critical. It is also used in some military-grade incendiary devices and smokeless propellants where high thermal conductivity and sustained combustion are required. Due to its density and shape, copper slug can also function as a kinetic component in certain non-lethal munitions, though this application is less common.