Chambers are finished, but barrels should be headspaced and installed by a qualified gunsmith
Please note that although many .308 AR bolt manufacturers advertise their bolts as compatible with DPMS pattern .308 AR rifles, lug and bolt face tolerances often vary widely between different manufacturers (as opposed to the AR-15, where there is a uniform industry standard). Criterion barrels are gauged at the factory with Fulton Armory .308 AR bolts. We have also had success in demo rifle testing with bolts from DPMS and JP Enterprises. If you have any questions regarding bolt compatibility, please email us at email@example.com.