A mounting bar system permitting infinite adjustability in mounting avionics-components trays and Dzus-mounted avionics in at least one aircraft cockpit instrument panel assembly. Each mounting bar is slotted along its longitudinal axis. The slot is made to include the shape of a T such that a wider channel exists below the opening of the slot. Spring-loaded nut assemblies set to receive mounting screws from the avionics-components trays are fit within the T slot. Friction provided by the spring holds the nut assembly at any desired location within the T slot. As the nut assembly can be positioned at any location within the T slot, the mounting bar can readily be adjusted to support any avionics-components tray intended for at least one aircraft cockpit instrument panel assembly.