Mark 5 nuclear bomb

Mark 5 nuclear bomb, side view.
The Mark 5 bomb displaying open doors at front are for insertion of nuclear core
View looking into the nose of a Mark 5, where the fissile pit and final explosive charge segment would be inserted.

The Mark 5 nuclear bomb and W5 nuclear warhead were a common core American nuclear weapon design, designed in the early 1950s and which saw service from 1952 to 1963.