M4-89 5.56x45 NATO Assembled Upper Receiver - M4-89 5.56x45 NATO 13.7" Bbl 13" M89 Rail W/Nox Brake
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Sons of Liberty Gun Works
Overview
The M4-89 5.56x45 NATO Assembled Upper Receiver from Sons of Liberty Gun Works is a complete upper designed for the AR-15 platform, featuring a 13.7-inch barrel optimized for 5.56 NATO ammunition. With a thread pitch of 1/2x28, it allows for easy attachment of muzzle devices, enhancing performance and customization options. This upper receiver is commonly found in shorter, maneuverable builds that prioritize compactness without sacrificing ballistic effectiveness.
Specifications
M4-89 5.56x45 NATO Assembled Upper Receiver - M4-89 5.56x45 NATO 13.7" Bbl 13" M89 Rail W/Nox Brake
Available Merchants(1)
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Stock Alert
Price and stock
The Sons of Liberty Gun Works M4-89 5.56x45 NATO Assembled Upper Receiver - M4-89 5.56x45 NATO 13.7" Bbl 13" M89 Rail W/Nox Brake was out of stock everywhere we track for all of September 2026, and today the one retailer we track is out of stock. Listed prices start at $950 at Brownells for when it comes back.
Prices checked · refreshed daily across 37 retailers
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