Calibers: 5.56 NATO, 22 ARC, 6 ARC, 300 BLK, 350 Legend, 450 Bushmaster. 16”, 18” (22 ARC and 6 ARC) stainless steel barrels. “FC” stands for forwarding charging, similar to a pump-action shotgun, to clear malfunctions. Introduced 2023. Several Cerakote finishes, several trigger options. Standard B5 Systems buttstock and grip; optional Bilson Arms Gen II RTC Rotating Buttstock.