 The 1940s also saw the creation of the National Slingshot Association, headquartered in San Marino, California, which organised slingshot clubs and competitions nationwide.Despite the slingshot's reputation as a tool of juvenile delinquents, the NSA reported that 80% of slingshot sales were to men over 30 years old, many of them professionals.John Milligan, a part-time manufacturer of the aluminium-framed John Milligan Special, a hunting slingshot, reported that about a third of his customers were physicians.