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(FN FAL), made at the Government Lithgow Small Arms Factory, and quantities of M16A1s.

Fred Riddle of Dupont Australia and Charles St. George worked together (with the input of Dupont USA) to select an appropriate engineering plastic for the pistol grip, handguards and butt-stock.

The Leader was originally imported into the U.S. by Ed Hoffman and Tim Painter of World Public Safety, CA. The Leader was exhibited at the New Orleans Shot Show and orders in excess of $3,000,000 were written. The original buyers/distributors were John Giovino NY, Bumble Bee CA and Ellett Brothers. These rifles are quite rare in the US as very few (less than 2000) made it into the country.

Charles St. George designed the production tooling and the factory at Smithfield began to initially turn out 200 units per month, which increased to 400 per month some months later. St. George developed a selective fire version (including a sub-machine gun version of the Leader) which attracted the interest of the Royal Australian Armoured Corps, as well as foreign arms companies, including Luigi Franchi (a subsidiary of Beretta) in Italy, Fábrica Militar de Braço de Prata in Portugal, and foreign militaries, such as the Sultanate of Oman Armed Forces. ATA Target Systems of Albury NSW hosted the visitors, and Charles St. George together with Terry Dinnen demonstrated the Leader weapons on ATA's Dart System. The Leader demonstration resulted in Oman placing trial weapon orders for 12 Leader select rifles and 12 Leader submachine guns.

During this period, Charles St. George departed for Europe and conducted demonstrations in Portugal, Malta and Italy. Luigi Franchi were very impressed with the Leader and wanted to purchase a manufacturing license with customers in Europe and Asia. Unfortunately, Jack Allen and Brian Shaw, the two other partners in Leader, were not able to conclude a satisfactory contract with Luigi Franchi. Franchi eventually developed their own weapon.

From a manufacturing undertaking, the Leader episode is indeed remarkable. Charles St. George had to convince Australian engineering companies that it was possible to make gun parts and that close tolerances were not imperative, as is the common belief. Barrels from Lithgow were too expensive so St. George designed and built his own button rifling machine using a self rotating button with a pushing motion. The barrel blanks were imported from Parker Hale in the United Kingdom with H&K providing the chamber machining details and Chartered Industries of Singapore supplied the 20 round M16 magazines.

The weapon is quite simple and tooling cost was kept to a minimum. The receiver was a simple 16 gauge steel square tube readily available and saved thousands of dollars in die costs.

In 1982 St. George split from both Brian Shaw and Jack Allan and moved on and established Armtech Pty Ltd. Leader Dynamics was subsequently sold off to a businessman who formed his own company, Australian Automatic Arms and started to make the Leader rifles in Tasmania.

Of interest to those that study weapons, designs and evolution, Barrett Firearms copied and uses the Leader Triangular breech bolt design for the M82A1 and its bolt action guns.