Action: Semi-Auto - Caliber: .300 AAC Blackout - Capacity: 30rd - Barrel: 8.5 Receiver Upper: Metal Reinforced Polymer Black - Receiver Lower: Metal Reinforced Polymer Black - Grip: A2 Synthetic Black - Handguard: 7 - Free Float Quad Rail - Weight: 4.95 lbs. - Complete fully-patented metal-reinforced Omni polymer lower receiver and inter lock hammer & trigger pin retainment system - Patent pending metal reinforced polymer Omni Hybrid MAXX Upper - Mil-Spec AR15 lower parts kit - Beveled mag well - Enhanced trigger guard - Includes Magpul PMAG magazines - Mil-Spec compatible