In the 1950s, while working with colleagues who were studying introduced wild goat, deer and tahr populations in New Zealand, Murdoch had the idea that the animals would be much easier to catch, examine and release if a dose of tranquilliser could be administered by projection from afar. Murdoch became experienced with repairing and modifying guns during World War II, as rifles and shot guns were not being imported into New Zealand at that time. With both motive and experience, Murdoch went on to develop a range of rifles, darts and pistols, which have had an enormous impact on the treatment and study of animals around the world.