A direct drive retrofit system for use with an M-16 or AR-15 rifle for conversion from an impingement system comprising: a gas block, the gas block having a barrel bore and a gas plug bore; a gas plug, the gas plug being inserted into the gas plug bore from the muzzle end; a bolt carrier key, the bolt carrier key being configured to mount directly to a bolt carrier; a rod, the rod being manufactured from a single continuous material stock; and a biasing means; wherein, the rod can be uninstalled without removal of a hand guard or the gas block by extracting the gas plug from the gas plug bore from the muzzle end, the actuating means releasing the rod, the rod being freely extracted thereafter by a user in a single piece.