Colt M4 to M5 Carbine 5.56x45mm NATO 10.3in M-LOK Upper Receiver Heavy Carbine Length 1-7 Twist 1/2x28 A2 Flash Hider Manganese Phosphate Black. 56x45mm NATO 10.3in M-LOK Upper Receiver. These AR15 Upper Receivers from the professional product specialists at Colt are designed using dependable and reliable resources to be able to supply you with a product which will be effective for quite some time. Designed using some of the most useful available substances and engineering these particular AR15 Upper Receivers through the product professionals at Colt will last you an unbelievably long time. Colt has been making high quality products for a number of years and the Colt M4 to M5 Carbine 5.56x45mm NATO 10.3in M-LOK Upper Receiver is their approach to demonstrating just how much they care. At OpticsPlanet we ensure that it is our obligation to obtain the perfect product for all your requirements and exhibiting the Colt M4 to M5 Carbine 5.56x45mm NATO 10.3in M-LOK Upper Receiver is something that we are delighted to offer. Specifications for Colt M4 to M5 Carbine 5.56x45mm NATO 10.3in M-LOK Upper Receiver: Manufacturer: Colt Caliber: 5.56x45mm NATO Barrel Length: 10.3 in Barrel Profile: Heavy Gas System Length: Carbine Length Barrel Twist Rate: 1-7 Firearms Threads Per Inch: 1/2x28 Handguard Type: Free-Float Muzzle Device: A2 Flash Hider Finish: Manganese Phosphate Color: Black Gun Model: M4 M16 AR-15 Fabric/Material: Aluminum Handguard Style: M-LOK w/ Top Picatinny Rail System Gun Rail: M-LOK Picatinny Gun Type: Rifle Gun Make: Colt AR Platform Bolt Carrier Group Included: MIL-SPEC Features of Colt M4 to M5 PDW Upper Reciever Kit: Package Contents: Colt M4 to M5 Carbine 5.56x45mm NATO 10.3in M-LOK Upper Receiver What firearm models does the manufacturer say Colt M4 to M5 Carbine 5.56x45mm NATO 10.3in M-LOK Upper Receiver is compatible with? The manufacturer says that Colt M4 to M5 Carbine 5.56x45mm NATO 10.3in M-LOK Upper Receiver is compatible with AR-15 M4 M16Colt CM556-10H-CK: M4 to M5 Carbine 5.56x45mm NATO 10.3in M-LOK Upper Receiver Heavy Carbine Length 1-7 Twist 1/2x28 A2 Flash Hider Manganese Phosphate Black