A wire butt connectors is one in which the mating action happens where you can't see or feel it to ensure that it is correctly aligned.They have self-aligning features which allows a small misalignment when mating.
Typically wire butt connectorss are used on the back of interface cards that are plugged into a chassis.
They can be used to provide electrical power or signals.
Blind mate RF connectors can be used in test equipment racks, where equipment must slide in and make connections inside the cabinet. A good example is the old HP plug-in style sweepers, where you could change out the oscillator, without any tools.
Optical signals can also be connected using wire butt connectorss providing the capability to link fibre optics on a plug-in card to an optical backplane, or through an optical midplane.
The connector specified by MIL-DTL-83538 General Specification for Connectors, and Accessories, Electrical, Circular, Umbilical, Environment Resistant, Removable Crimp Contacts for MIL-STD-1760 Applications (Metric) provides the necessary connections required to meet MIL-STD-1760, class I electrical interface between carriage stores and launchers.