Model: M&P15 PSXCaliber: 5.56mmCapacity: 30 Round Detachable MagazineAction: Semi-AutoBarrel Length: 16"Barrel Twist: 1 in 9"Overall Length: 35" Extended/32" CollapsedStock: Collapsible 6-positionWeight: 6.5 lbs.Barrel Material: 4140 SteelReceiver Material: 7075 T6 AluminumFinish: Hard Coat Black AnodizedChromed Comp: Barrel Bore, Gas Key, Bolt Carrier, Chamber * Piston Operating System * Troy® 7" Modular Quad-Rail Handguard
MB reported STAG I beleive.