Provided are systems and methods related to firearm trigger assemblies. The method includes the steps of forming a first isolated layer on the substrate having a plurality of parallel bit lines. The first and second gear mechanisms are configured to switch between transmission and non-transmission of a driving force to the cleaning roller according to rotational direction of the motor. A ring of bolts holds the sections together, and the shuttle valve is contained at least partially within the envelope formed by the ring. The barrier is secured in the blower tube by a snap engagement with the retention feature.