Pro-Shot's Dual purpose design chamber mop can clean and lubricate both the chamber and locking lug recesses of your AR15/M4/M16 platform rifle. The longer smaller part of the mop reaches the chamber area, while the larger diameter is meant to reach the star chamber/ locking lug recess area. Excellent for use after bristled chamber brush for removing excess carbon fouling or excess CLP during the cleaning process. This Military style model is compatible with .223/5.56mm rifle.