An instrument for applying clips in surgery particularly suited for microsurgery with instrument chassis and cover joined to form housing supporting handle and clip handling components, the handle for squeeze and release action to develop linear reciprocation motion of fixed excursion, the clip handling components for feeding a stack of clips one-by-one into instrument clip crimping jaws for application at a surgical site, an anti-backup mechanism constraining handle action to full pull and release strokes, and an instrument lock-out mechanism to prevent instrument operation after last clip in stack is used. Clip handling components of magazine carrier, magazine, clip stack, clip pusher, pusher spring, and pusher spring shaft are inserted into instrument in upwardly open channel and secured by pusher spring cover.
