Alan Rickman decided to take the part because filming was taking place in Australia. He always wanted to visit Australia.
Tom Selleck said his scariest moment ever as an actor occurred while standing on a boulder near Alice Springs, Australia, over a cliff. "I had to look down, and it was a big boulder so they said, "Just go stand on the boulder, you'll be fine." But the boulder started rattling back and forth, and and I said, "Maybe you need to tie me off."
The film was to have been Steve McQueen's next film after The Hunter (1980), but he fell ill shortly after making that, so the project was scrapped. It was revived several times throughout the 1980s, with various stars in mind for the lead. Harrison Ford was offered the lead role, but turned it down because he considered it too visibly similar to Indiana Jones. The lead was first offered to Tom Selleck in 1985. He had to turn it down because of his commitment to Magnum, P.I. (1980). When the series concluded in 1988, he quickly asked if the role was still available, and accepted it. The producers spent another year gathering a reasonable budget.
Three Sharps rifles were built for the film: one for shooting, one as a club in the fight scenes, and a back-up weapon in case one was damaged. Tom Selleck requested to keep the 3 rifles built for the film. He had two of them reconditioned to remove scratches and straighten and tighten some of the moving parts. Years later, he signed and auctioned 2 of them as part of a fundraiser for the National Rifle Association, of which he is a national board member. Selleck donated the third rifle, with its fringed leather scabbard, and belt knife to the Brownell's Family Museum.
Sharps Rifles are now so inseparably related to this film that they are commonly nicknamed "Quigley guns." Sales for such weapons increased by over 1000% following the film's release, especially in the United States and Australia, and continue through 2013.