Chiappa Firearms M4-22 Gen II .22 Long Rifle 16in Picatinny Upper Receiver BBL 1/2x28 Threaded 28 Round Magazine Black. 22LR rifle perfect for plinking of training. The forend is a 11.8in long Quad Picatinny with a 16in steel barrel. Specifications for Chiappa Firearms M4-22 Gen II .22 Long Rifle 16in Picatinny Upper Receiver: Manufacturer: Chiappa Firearms Caliber: .22 Long Rifle Barrel Length: 16 in Barrel Profile: Heavy Contour Barrel Twist Rate: 1-16 Firearms Threads Per Inch: 1/2x28 Finish: Matte Color: Black Gun Model: M4 Fabric/Material: Polymer Handguard Length: 11.8 in Gun Rail: Quad Picatinny Gun Type: Rifle Gun Make: Colt Barrel Material: Steel Weight: 4.63 lb Magazine Included: Yes Package Contents: Chiappa Firearms M4-22 Gen II .22 Long Rifle 16in Picatinny Upper Receiver What firearm models does the manufacturer say Chiappa Firearms M4-22 Gen II .22 Long Rifle 16in Picatinny Upper Receiver is compatible with? The manufacturer says that Chiappa Firearms M4-22 Gen II .22 Long Rifle 16in Picatinny Upper Receiver is compatible with M4Chiappa Firearms 500.068: M4-22 Gen II .22 Long Rifle 16in Picatinny Upper Receiver BBL 1/2x28 Threaded 28 Round Magazine Black