The Sons of Liberty M4-L89 Series offers the performance and precision all Sons of Liberty firearms are known for. These premium AR-platforms are available in 5.56 NATO and .300 BLK, and come in multiple barrel lengths. All M4-L89 models are equipped with a proprietary 4150CoMOV barrel with a V2 profile and a QPQ corrosion resistant finish. Each M4-L89 also features an ambidextrous Liberty Charging Handle, Liberty Fighting Trigger, and a Quick Ambi Selector. Additionally, the M4-L89 features a 9 position A5 length buffer system with a Sprinco Green Spring. Features of the Sons of Liberty M4-L89 Series: Available in 5.56 NATO and .300 BLK 4150CoMOV barrel with a V2 profile QPQ corrosion resistant barrel finish Liberty Charging Handle Liberty Fighting Trigger Quick Ambi Selector 9 position A5 length buffer system w/ Sprinco Green Spring Sons of Liberty Gun Works SOLGW M4-L89 5.56mm 13.7" Broadsword Upper Rifle w/SF Compatible/ROTEX Mount M4-L89BS-13.7-SF