High Quality Content by WIKIPEDIA articles! The Leader T2 MK5 Series weapons were chambered for the 5.56 mm cartridge and manufactured by Leader Dynamics of Smithfield, NSW, Australia. (1978-1982/1983) The Leader was the brainchild of weapons designer Charles St. George. What was unique about this endeavor was that Australia had never designed or manufactured its own commercial gas operated semi-automatic rifle. The Australian Army at the time used the L1A1, made at the Government Lithgow Small Arms Factory, and significant quantities of M16A1 rifles.