(written from a Production point of view)
Gregory "Greg" Joe Gault is a stuntman, stunt actor, and stunt coordinator who served as stunt double for David Warner in Star Trek VI: The Undiscovered Country. He doubled Warner during the wire scenes with the rigging harness and also his fall on the ground. He received no on-screen credit and was identified by the name tag of his costume which was sold off on It's A Wrap! sale and auction on eBay  and the call sheets of the movie.
Gault has appeared in films such as The Capture of Bigfoot (1979), Butterfly (1982, with Edward Laurence Albert and stunts by Janet Brady), Invasion U.S.A. (1985, with Richard Lynch, Jon De Vries, Stephen Markle, Nick Ramus, Maria Doest, and stunts by Chuck Courtney, B.J. Davis, Al Jones, Alan Marcus, Eric Norris, Don Pulford, Don Ruffin, and Lincoln Simonds), The Delta Force (1986, with Eric Norris and stunts by B.J. Davis), King Kong Lives (1986, with Leon Rippy, Herschel Sparber, Mike Starr, and stunts by Ken Bates, Monty Cox, Bud Davis, Randy Hall, Beth Nufer, and Dennis Scott), Who's That Girl? (1987, with Bibi Besch, Cecile Callan, Ron Taylor, Mike Starr, Laura Drake, Roy Brocksmith, Faith Minton, Darwyn Carson, Pat Romano, Lloyd Kino, and stunts by Monty Cox, Bud Davis, Randy Hall, Don Pulford, Branscombe Richmond, and Dennis Scott), Bulletproof (1988, with Thalmus Rasulala, Jorge Cervera, Jr., Christopher Doyle, Cary-Hiroyuki Tagawa, and stunts by Rick Avery, John Escobar, Cole McKay, Joyce McNeal, Jimmy Ortega, Mic Rodgers, and Spike Silver), Feds (1988, with Kenneth Marshall, Larry Cedar, Don Stark, and Rick Avery), Shocker (1989, with John Tesh, Dendrie Taylor, Stephen R. Hudis, Brent Spiner, and stunts by Charlie Brewer, Dennis Madalone, Patricia Tallman, and Tim Trella), A Gnome Named Gnorm (1990), Grand Canyon (1991, with Alfre Woodard and Tina Lifford), Richie Rich (1994, with John Larroquette, Rick Worthy, Frank Welker, and stunts by Charlie Brewer and Tabby Hanson), Eraser (1996, with Vanessa Williams), and The Protector (1998, with Ron Perlman, Clint Howard, John Rhys-Davies, and Gary Kasper).