One of the original members of the Fifty Caliber Shooters Assn., Inc (FCSA) Rock is one of only four persons granted a complimentary life membership for his dedication and service to the "advancement of the sporting uses of the 50 BMG cartridge" by the membership of FCSA. A long time competitor in the sport of long distance rifle competition, he is known far and wide for his contributions to the law enforcement field and for his research and development in support of our military forces. The McMillan family is "the most respected family name in the firearms industry". Raised under the tutelage of his famous father Gale McMillan, Rock has continued his father's work and brought the McMillan family name to a higher level with his improvements in technology and his understanding of the machining industry. Rock has served as a member of the Board of Directors of the Fifty Caliber Institute for the past decade on the front lines in a continuous fight to protect America’s 2nd Amendment right to Keep and Bear Arms.