Calibers (w/ barrel twists): 5.56 NATO, 22 ARC (1:7), 6 ARC (1:7), 300 BLK, 350 Legend, 338 ARC (1:8), 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. Direct impingement gas actions, free-float handguards. BilsonArms.com. Introduced 2023. Several Cerakote finishes, several trigger options. Standard B5 Systems buttstock and grip; optional Bilson Arms Gen II RTC Rotating Buttstock. Add $100 for FDE finish. Made in the USA. Based in Broussard, La. Subtract 23% for the Forward charging upper assembly only.