trigger shaft

trigger shaft

[′trig·ər ‚shaft]
(ordnance)
The shaft which passes transversely through the breechblock and firing lock of a gun and whose arm is actuated by the firing mechanism; movement of the arm rotates the shaft and thus imparts movement to the trigger fork of the firing lock.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.