Abstract: In a spring-loaded missile projecting device such as a bow including a center holding part with outwardly projecting support portions having bow members pivotally mounted thereto with a string extending between the free outer ends of the bow members, elbow linkages are arranged between the support portions and the bow members such that the elbows are slightly bent away from the string when the string is straight and the elbow linkages are spring-loaded so as to be forced toward the string for tensioning the string, so as to provide for a relatively large initial string tensioning force which does not appreciably increase by pulling out of the string thereby generating a relatively constant arrow-accelerating force and requiring a relatively low holding force.