The Precision Armament M4 Shoulderless Thread Adapter allows thread adapter to remain fully concealed under muzzle device for a continuous, streamline look. Muzzle device seats directly against barrel shoulder maintaining full thread joint strength and providing more accurate alignment to bore. Internal and external threads are single point cut in same operation to tight UNEF Class-3 tolerances for perfect concentricity and alignment. The M4 muzzle thread adapter is precision CNC machined from pre-hardened HTSR 400-series stainless steel bar for superior heat and corrosion resistance.