M4-89 300 AAC Blackout Assembled Upper Receiver - M4-89 300 AAC Blackout 13.9'''' Bbl 13'''' M89 Rail & Flash Hider
Click to see full view
Sons of Liberty Gun Works
Overview
The M4-89 300 AAC Blackout Assembled Upper Receiver from Sons of Liberty Gun Works is a complete upper designed specifically for the AR-15 platform, featuring a 13.9-inch barrel optimized for 300 Blackout ammunition. This setup allows for efficient performance in both subsonic and supersonic loads, making it versatile for various shooting applications. Commonly found in builds that prioritize 300 Blackout caliber, this upper receiver is ideal for those looking to enhance their firearm's capabilities in a compact configuration.
Specifications
M4-89 300 AAC Blackout Assembled Upper Receiver - M4-89 300 AAC Blackout 13.9'''' Bbl 13'''' M89 Rail & Flash Hider
Build history on GunPartPicker
Builders on GunPartPicker first added the Sons of Liberty Gun Works M4-89 300 AAC Blackout Assembled Upper Receiver - M4-89 300 AAC Blackout 13.9'''' Bbl 13'''' M89 Rail & Flash Hider to a build in February 2026.
Today none of the 2 retailers we track has it in stock right now. Listed prices start at $712.50 at Brownells for when it comes back.
Updated · from real builds on GunPartPicker · Prices checked · refreshed daily across 35 retailers
Not sure which upper receiver to pick?
We ranked every upper receiver by how often it shows up in real builds on GunPartPicker.
Read the guide: Most Popular AR-15 Upper Receivers →Check it against the live catalog:
Frequently Built With
Popular alongside upper receivers on GunPartPicker
Aero Precision M4E1 Complete Lower Receiver W/MOE SL Grip & SL-S Carbine Stock
Aero Precision AR-15 Breach Charging Handle Ambidextrous Small Levers
Geissele Automatics AR-15 SSA-E X Lightning Bow Trigger
Bravo Company M16 Bolt Carrier Group Black
Magpul AFG-2 Angled Fore Grip - Black
Magpul AR-15 MOE Stock Collapsible Mil-Spec Black
No reviews yet. Be the first to review this product!