Abstract: A firearm comprised of an upper receiver defining a bolt passage and a lower receiver configured to connect to the upper receiver and having a mount registered with the bolt passage. A buffer tube connects to the mount in registration with the bolt passage. The buffer tube includes a forward portion connected to the mount and a rear portion telescopically connected to the forward portion and operable to move in a range of positions with respect to the upper receiver and a lock mechanism operable to secure the rear portion in a selected position.

Abstract: A speaker system and approach facilitates flexible installation and removal of an audio speaker into a structure. According to an example embodiment of the present invention, a speaker system includes mounting hardware and audio components with a fastening arrangement that facilitates the fastening of the mounting hardware to a structure and the audio components to the mounting hardware. The speaker system is amenable to a one-piece installation wherein the audio components are coupled to the mounting hardware during installation, as well as a two-piece installation wherein the mounting hardware is attached to the structure separately from the audio components. After installation, the one-piece and two-piece approaches both facilitate the flexible removal of the audio components from the mounting hardware.