GLOCK OEM Threaded Barrel for Glock 21 Gen3/Gen4 – 45 ACP

GLOCK OEM Threaded Barrel for Glock 21 Gen3/Gen4 – 45 ACP

The GLOCK OEM threaded barrel for Glock 21 Gen3 and Gen4 is the factory-original upgrade for shooters who want suppressor compatibility without sacrificing reliability or fit. Precision-engineered from high-quality steel with Glock’s renowned cold-hammer-forged process, this barrel maintains the legendary durability, accuracy, and longevity of your Glock 21. Available in M16x1 LH or .578×28 RH thread pitches (with included metal thread protector), it allows easy attachment of suppressors, compensators, or other muzzle devices. The extended length accommodates threading while keeping the pistol compact enough for everyday carry or duty use.

This drop-in barrel requires no fitting or modifications — simply swap it in and maintain full Glock warranty compliance. Perfect for .45 ACP enthusiasts adding suppressed shooting capability to their Glock 21 platform, this OEM threaded barrel delivers sub-MOA potential, excellent corrosion resistance, and seamless integration with factory sights and slide. Upgrade your Glock 21 today with the only threaded barrel made by Glock themselves.

• Model: GLOCK OEM Threaded Barrel (part numbers commonly referenced: 39895 for M16x1 LH version; .578×28 RH version also available)
• Compatibility: Glock 21 Gen3 and Gen4 (does not fit Gen5 due to different barrel lug design)
• Caliber: .45 ACP
• Barrel Length: Approximately 4.49–5.06 inches (extended to accommodate threads; exact length varies slightly by thread pitch version)
• Material: High-quality steel (GLOCK proprietary cold-hammer-forged process)
• Finish: Black (standard GLOCK Tenifer-like treatment for corrosion resistance)
• Thread Pitch:
  • Common: M16x1 LH (left-hand threads)
  • Alternative: .578×28 RH (right-hand threads, more suppressor-friendly in US market)
• Thread Protector: Included (metal thread protector)
• Features: Factory original equipment, drop-in fit (no gunsmithing required), maintains Glock reliability and accuracy, designed for suppressor or compensator use

shop now

View specs for GLOCK 21 threaded barrel