Caliber: 5.56 NATO. Barrels: 13.7” and 16” Sons of Liberty Gun Works 4150 CoMOV 1:7” MPI HPT. 1/2-28 threaded muzzle. .750” gas block journal with appropriately sized gas port. Other SOL lines include EX03 Series, M4-89 Series, and M4-L89 Series. MK-10 series of large-frame AR-pattern rifles introduced 2024. SEE POLITICAL PANIC PRICING.