Faxon Firearm's 9mm barrels are manufactured from 4150 GBQ Steel. For AR Carbines, they use 1/10 twist to ensure stabilization across all grains of 9mm loadings. Further, they feature QPQ Black Nitride or FDE coating for superior corrosion resistance and longevity. Muzzles have A 1/2" x 28 threads, are target crowned, and have concentric threads ready for suppressor use. All barrels are fully magnetic particle inspected. Note: While the barrels are threaded to 1/2-28 please make sure to use the proper diameter muzzle device. Mfg: Faxon Firearms