Steel bolt is shot-peened for extra surface hardness, then magnetic particle inspected (MPI) for cracks and flaws to ensure reliability and long service life. Models available for rifles chambered in 5.56mm/.223. Comes completely assembled, with gas rings, extractor, and ejector installed.
AR-15, Issue:10, Page:011
Big Book Catalog, Issue:68, Page:012
SPECS: Carpenter 158 steel, phosphate coated, matte black.