The Bisley Wool Mop is a general firearm cleaning accessory used for the finishing stage of barrel maintenance. It is made from tightly wound wool fibres attached to a central core, designed to be used with a standard cleaning rod. The mop comes in different sizes depending on calibre or gauge, allowing it to fit snugly inside shotgun, rifle, or airgun barrels without damaging the internal surface.

Its main function is to apply a thin, even layer of oil inside the barrel after cleaning. The wool fibres are highly absorbent, so they hold cleaning oil well and spread it evenly as the mop is pushed and pulled through the bore. This helps protect the metal from moisture and corrosion during storage. At the same time, the fibres pick up any remaining fine dust, loosened fouling, or residue left after brushing or patching.

The wool mop is not designed for aggressive cleaning. Instead, it is used after heavier tools such as bronze brushes or jags have already removed the bulk of fouling. Its soft construction ensures it will not scratch or wear the barrel, making it safe for regular use as part of routine maintenance.

In practice, it is one of the final steps in a cleaning process. Once the barrel is mechanically cleaned, the mop is used to leave a clean, lightly oiled surface that helps maintain long-term condition and prevent rust. It is a simple but important tool in keeping firearms properly maintained.