An expandable modular rack for storing at least one pistol of any width and/or at least one similarly configured item in its/their normal upright position. The expandable modular rack includes at least one first member, at least one second member, and at least one third member. The at least one first member, the at least one second member, and the at least one third member are interchangeably attached to each other, side-by-side, so as to form at least one bay. Each bay is defined by a vertical portion and a horizontal portion. The vertical portion of each bay supports the barrel of an associated pistol or an associated similarly configured item, the horizontal portion of each bay supports the heel of the grip of the associated pistol or the associated similarly configured item, and each bay is of varying width, thereby allowing each bay to store the associated pistol or the associated similarly configured item of any width in its normal upright position.