Grey Ghost Precision Complete Upper 5.56mm 20.12in 10.5in Low Profile Carbine 1-7 1x2/28 M-LOK Black. 56 10.5 Complete upper is exactly what you need to build a AR pistol or SBR using the same quality parts offered in complete GGP rifles but in a smaller package Specifications for Grey Ghost Precision 10.5 inch 5.56mm Complete Upper: Manufacturer: Grey Ghost Precision Caliber: 5.56mm Overall Length: 20.125 in Barrel Length: 10.5 in Barrel Profile: Medium Gas System Length: Carbine Length Barrel Twist Rate: 1-8 Threads per Inch: 1/2x28 Handguard Type: Drop-In Muzzle Device: Thread Protector 1/2-28 Finish: Black Anodized Color: Black Fabric/Material: 7075-T651 Aluminum 6061-T6 Aluminum Handguard Length: 9.25 in Gun Rail: M-LOK Gun Make: AR Platform Gun Model: AR-15 Weight: 3.6 lb Magazine Included: No Mount Type: M-LOK Features of Grey Ghost Precision 10.5 inch 5.56mm Complete Upper GGP MKII 7075-T651 Billet Upper Receiver ? GGP MKII 9.25" M-LOK handguard ? True Black Type III Class 2 Mil Spec hard coat anodize ? 10.5" 5.56 barrel 1x8 twist 1/2x28 threaded muzzle ? Carbine length Gas ? GGP 5.56 cal Muzzle Brake ? Low-Profile Gas Block ? Bolt Carrier Group is Black Nitrided and MP/MPI tested ? Battle Arms Development RACK AR-15 Charging Handle ? No sights or optics included Package Contents: Grey Ghost Precision 10.5 inch 5.56mm Complete Upper What firearm models does the manufacturer say Grey Ghost Precision 10.5 inch 5.56mm Complete Upper is compatible with? The manufacturer says that Grey Ghost Precision 10.5 inch 5.56mm Complete Upper is compatible with AR-15Grey Ghost Precision GGP-556-10-UC: Complete Upper 5.56mm 20.12in 10.5in Low Profile Carbine 1-7 1x2/28 M-LOK Black