[citation needed] In 1969 he was elected to the Australian House of Representatives as the Labor member for Kingston, defeating Liberal MP Kay Brownbill.

He held the seat until 1975, when he was defeated by the Liberal candidate, Grant Chapman, with a swing of over 12 percent.

[3] In 1983 Gun was appointed chair of the Commonwealth Government's Interim National Occupational Health and Safety Commission.

The Minister for Employment and Industrial Relations (Ralph Willis) quoted his qualifications as: In 1990 when he was a senior lecturer in occupational and environmental health at the University of Adelaide he published the results of a study which suggested that the incidence of repetitive strain injury (RSI) was declining in South Australia.

[6][3] As a teenager, Gun was a jazz musician of some local celebrity, leader of "Richie Gun's Collegians", a King Oliver / Louis Armstrong inspired band, and has been credited with giving Ted Nettelbeck his first experience in public performance.