Quick detachable gun barrel coupling member

A coupling member for quick and easily attaching and detaching a firearm accessory to the front end of the gun barrel of a firearm that has at least three radially extending lug members adjacent its front end formed at predetermined spaced intervals from each other around its perimeter comprising:

• a tubular sleeve having a front end, a rear end, an outer surface and an inner surface;
• the inner surface of said tubular sleeve adjacent its front end having an internally threaded portion having a left hand thread;
• the rear end of said tubular sleeve having at least three circumferentially spaced longitudinally extending notches, said notches each having a bottom wall and laterally spaced side walls;
• said laterally spaced notches forming longitudinally extending finger members between them, said finger members having radially inwardly extending lug members each having a top wall, a bottom wall, laterally spaced side walls and an inner wall surface;
• and
• means for limiting rotational motion of said coupling member after it would be installed on the front end of the gun barrel of a firearm.