An apparatus and method for easily, quickly and reliably attaching a noise suppressor or other auxiliary device to the muzzle end of a firearm barrel and for easily, quickly and reliably removing the noise suppressor or other auxiliary device there from through the novel ideal of providing two or more non equal relieved areas of thread. My invention also provides an internal o-ring to provide friction between the muzzle adaptor and the thread mount of a noise suppressor or other auxiliary device.