Rail attachment mounting tool and locking bar

An accessory mount system for a rail of a gun, said system comprising:

• a locking bar configured to prevent rotation of a pair of thumb hex fittings of the accessory mount system when installed on the pair of thumb hex fittings, said locking bar comprising:
• a main body configured to extend longitudinally when the accessory mount system is installed on the rail and the gun is assembled and in an upright position;
• a pair of opposing sidewalls extending laterally from the main body when the accessory mount system is installed on the rail and the gun is assembled and in an upright position;
• a pair of lips, each lip of the pair of lips extending from a sidewall of the pair of opposing sidewalls, wherein the pair of lips extend toward one another;
• and
• a retaining device configured to prevent longitudinal movement of the main body when the locking bar is installed on the pair of thumb hex fittings.