Sons of Liberty M4-89-14.5: If youre looking for your next high-quality AR-15 rifle build, then a Sons of Liberty M4-89 barreled upper receiver is a great place to start. This receiver is manufactured with strict quality control, plus features an ejection port cover, forward assist, and an integral Picatinny rail that extends the length of the handguard. There is a combat grade barrel at the heart of the M4-89, which is magnetic particle inspected and high pressure tested. Sons of Liberty includes their NOX Flash Hider which is pinned and ready to mount a Dead Air Sandman or Nomad suppressor. Bolt Carrier Group & Charging Handle NOT Included. Bolt Carrier Group & Charging Handle NOT Included.