An improved firearm takedown mechanism is provided, which in a retention position prevents removal of both a slide and barrel assembly and a trigger assembly, but when manually positioned out of the retention position allows easy removal of both the slide and barrel assembly and the trigger assembly without the use of tools. A firearm takedown mechanism is provided having a first element with opposing ends separated by a longitudinal axis with a major and minor surface extending outwardly from the axis, and respectively adapted to prevent and allow removal of a slide and barrel assembly. An improved method for firearm takedown provides that after moving a takedown mechanism from a retention position, both a slide and barrel assembly and a trigger assembly are manually removed.