ABC RIFLE COMPANY AR .40 S&W Billet Pistol 4in Barrel Custom M-LOK Handguard Complete Upper Receiver w/BCG And Charging Handle Tungsten. 40 S&W upper features a 6061-T6 billet aluminum receiver cut to mil-spec tolerances. Its fitted with a 4in top-cut MLOK handguard from ABC Rifle Co complete with an integrated handstop for enhanced control. The 4in 4150 CMV barrel with a 1:16 twist pairs perfectly with the direct-blowback system and its compatible with both Colt and Glock-style lowers. A 7075 aluminum flash can redirects muzzle blast forward while the nitride-finished .40 S&W/10mm BCG ensures smooth cycling. Finished with a mil-spec ejection port cover forward assist and forged charging handle. Specifications for ABC RIFLE COMPANY AR .40 S&W Billet Pistol 4in Barrel Custom 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: 1-16 Threads per Inch: 5/8x24 Muzzle Device: Muzzle Diverter Flash Can Finish: Cerakote Handguard Length: 4 in Gun Rail: M-LOK Picatinny Gun Make: AR Platform Barrel Material: Steel Bolt Carrier Group Included: MIL-SPEC Charging Handle Included: MIL-SPEC Projectile Caliber: .40 Caliber Package Contents: ABC RIFLE COMPANY AR .40 S&W Billet Pistol 4in Barrel Custom M-LOK Handguard Complete Upper Receiver w/BCG And Charging Handle ABC RIFLE COMPANY UA40B-MLHSTP4-TNG: AR .40 S&W Billet Pistol 4in Barrel Custom M-LOK Handguard Complete Upper Receiver w/BCG And Charging Handle Tungsten