The present invention provides for a system and method for easily, quickly and reliably attaching a sound suppressor or other auxiliary device to the muzzle end of a firearm barrel, and for easily and quickly removing such device therefrom. Moreover, the invention will allow any suppressor—threaded or unthreaded—to quickly, easily and reliably attach to a firearm utilizing a dual part system. The dual part system comprises a barrel adapter having the ability to attach directly to a non-threaded suppressor or a quick disconnect suppressor, or connect to a threaded suppressor utilizing a supplemental coupling adapter which connects to existing threaded suppressors.