US Patent 9212879 Firearm cleaning shell

A bore cleaning device is disclosed including a propellant providing a force to push the projectile down the bore of the firearm, a frame including a plurality of collapsible legs, and a cylindrically-shaped cleaning agent installed around the legs. The frame further includes a lower charge cap configured to receive the force of the propellant and a rigid front end cap. The provided force creates a crushing force upon the frame. The crushing force causes the legs to collapse and provide an outward force upon the cleaning agent, wherein the outward force causes intimate contact between the cleaning agent and the bore as the device travels along the bore.