This .40 S&W drop-in replacement barrel fits Glock 23 Gen 1, Gen 2, Gen 3, and Gen 4 pistols. No fitting, no gunsmithing - it goes straight into a factory or aftermarket Glock 23 slide using the existing recoil spring assembly. Machined from 4150 chrome moly vanadium steel and finished in black nitride for surface hardness, corrosion resistance, and a matte black look that blends with most slide finishes. Chamber and bore dimensions match factory Glock 23 spec, so headspace and feed-ramp geometry stay correct with quality .40 S&W range and duty ammunition. Caliber: .40 S&W Fits: Glock 23 Gen 1-4 Material: 4150 chrome moly vanadium steel Finish: black nitride - matte, hardened surface Twist rate: 1:16 Drop-in: no fitting required for Glock 23 Gen 1-4 slides Lightly oil the exterior and feed ramp before your first range session and run 50-100 rounds of quality .40 S&W to break the barrel in with your slide and recoil spring. Always confirm function with your specific load before carry. Verify generation and frame compatibility before installation - this barrel is not configured for Gen 5 Glock 23. DISCLAIMER: GLOCK is a federally registered trademark of GLOCK, Inc. and is one of many trademarks owned by GLOCK, Inc. or GLOCK Ges.m.b.H. Neither 3CR Tactical nor this site are affiliated with, or endorsed by, GLOCK, Inc. or GLOCK Ges.m.b.H. The use of "GLOCK" on this page is merely to advertise the sale of aftermarket GLOCK pistol components. For genuine GLOCK, Inc. products, visit www.glock.com.