ABC RIFLE COMPANY AR .40 S&W Pistol 4in Barrel M-LOK Handguard Complete Upper Receiver w/BCG And Charging Handle Bronze. The 4in 4150 CMV barrel with a 1:16 twist is chambered in .40 S&W and designed for direct-blowback operation delivering solid reliability and smooth cycling. Compatible with both Colt and Glock-style lowers it features a 5/8x24 7075 aluminum flash can to redirect blast forward. Outfitted with a nitride-finished .40 S&W/10mm BCG mil-spec stamped steel ejection port cover forward assist and a forged 6061-T6 charging handle for dependable function. Specifications for ABC RIFLE COMPANY AR .40 S&W Pistol 4in Barrel M-LOK Handguard Complete Upper Receiver w/BCG And Charging Handle: Manufacturer: ABC RIFLE COMPANY Caliber: .40 S&W Barrel Length: 4 in Barrel Twist Rate: 1-10 Threads per Inch: 5/8x24 Muzzle Device: Muzzle Diverter Flash Can Fabric/Material: 7075 Aluminum Handguard Length: 4.5 in Gun Rail: M-LOK Gun Type: Rifle Gun Make: AR Platform Gun Model: AR-15 Bolt Carrier Group Included: MIL-SPEC Charging Handle Included: MIL-SPEC Projectile Caliber: .40 Caliber Package Contents: ABC RIFLE COMPANY AR .40 S&W Pistol 4in Barrel M-LOK Handguard Complete Upper Receiver w/BCG And Charging Handle What firearm models does the manufacturer say ABC RIFLE COMPANY AR .40 S&W Pistol 4in Barrel M-LOK Handguard Complete Upper Receiver w/BCG And Charging Handle is compatible with? The manufacturer says that ABC RIFLE COMPANY AR .40 S&W Pistol 4in Barrel M-LOK Handguard Complete Upper Receiver w/BCG And Charging Handle is compatible with AR-15ABC RIFLE COMPANY UA40-BR4-ML4-BB: AR .40 S&W Pistol 4in Barrel M-LOK Handguard Complete Upper Receiver w/BCG And Charging Handle Bronze