This is a Garrett ballistic actuator of the ALCM missile. It is the actuator that causes the wings and aerodynamic surfaces to unfold. It is ballistic in that it has a small propellant to get it started and it stops via an oil damper system.
U.S. Air Force
1975
<a rel="nofollow" class="external text" href="https://babel.hathitrust.org/cgi/imgsrv/download/pdf?id=umn.31951d03556686k;orient=0;size=100;seq=1516;attachment=0">Hearings on military posture and H.R. 3689</a>, Pt. 4, Page 5260