A mounting assembly for a firearm muzzle attachment includes an attachment mount with a clutch assembly. A muzzle attachment can be secured to the distal end portion of the attachment mount. The attachment mount is configured to removably attach the muzzle attachment to a muzzle adapter installed on the end of a barrel. A clutch assembly on the attachment mount is operable between a locked position and an unlocked position. In the locked position, the clutch assembly frictionally engages the muzzle adapter to inhibit loosening rotation of the muzzle attachment relative to the muzzle adapter. In the unlocked position, the clutch assembly disengages from the muzzle adapter to permit loosening rotation of the attachment mount relative to the muzzle adapter. A method of use and a locking nut are also disclosed.