Great article about the guy who, for like a year, was set too play the drill sargent in Full Metal Jacket until losing it to R. Lee Emery:

Thirty two years after the film opened, Colceri remains best known for his work in Full Metal Jacket, though in a twist that's become part of the film's lore, he spent months preparing for a role he never got to play. After some behind-the-scenes maneuvering, technical adviser R. Lee Ermey convinced Kubrick to give him the part, with the filmmaker moving Colceri to the small, yet still memorable, role of the helicopter door gunner who famously shouted "Get some!" as he murdered Vietnamese civilians.