Provided herein is a fire sprinkler assembly including a bracket hub coupled to a bracket bar, and an adjustable drop coupled to the bracket hub. The adjustable drop may include an inner casing and an outer casing surrounding the inner casing, wherein the inner and outer casings include corresponding threading to permit rotation therebetween for adjusting an axial height, along a lengthwise axis, of the inner casing. In some approaches, a flexible metal conduit is directly coupled to a distal end of the inner casing or the outer casing. In some approaches, the inner casing includes a bellow disposed within an interior of the outer casing, the bellow having an expandable central component permitting contraction or expansion, which allows a sprinkler head coupled to the inner casing to be raised or lowered, accordingly.