*Threaded Barrel (Black) for Glock 23, .40 CAL-9/16X24 Threads.Threaded Barrel (Black) for Glock 21, .40 CAL-9/16X24 Threads. This Black Oxide match grade replacement barrel is manufactured from the highest grade mill select steel. CNC machined and heat treated, providing a life time of service and unparalleled accuracy at an affordable price. The standard groove and land rifling make this an excellent choice for those who wish to shoot lead, plated or jacketed bullets. Can be used in factory ported or stock pistols. Intended for use in the Glock 21 pistol only. Threaded 9/16x24 to fit most suppressors (or similar). Special features include: Black Oxide Finish Ready to use, pre-fit drop in. No gun smithing required. Precision machined from heat treated 416R stainless forgings. Over sized lock-up area produces greater shot-to-shot accuracy. Tighter dimensions than the original. Polished feed ramp and bore, diamond turned exterior Maximum chamber support, improved feed ramp design. Match grade broach cut rifling and target crown. Ok to use lead, plated or jacketed bullets. Fits Glock 23 only, .40 cal***OUT OF STOCK**