The monobloc upper features a hm barrel with an integral machined patented gas block, and a carbine gas system.It is also 4150 chromoly, match grade, tripled honed, and button rifled.Its handguard is free-floating and uses a picatinny rial, magpul m-lok, and machined from 6061-t6 aluminum.Upper and lower receiver are made of 7075-t6 aluminum with a hard coat anodized finish.The monobloc upper also includes a patented hmb bolt, mil-spec components, charging handle, and a dust cover with an american flag.Receiver Finish: Black Hard Coat AnodizedCaliber: 223 RemSights: 16" to 16.99"Barrel Length: 16"Twist: 1:8"Barrel Description: 4150 Chrome Moly Match GradeBarrel Finish: Black CerakoteHandguards: 10.37" M-LOK Free-FloatHandguard Finish: Black Hard Coat AnodizedBarrel Length Range: 12" to 12.99"