The Windham Weaponry R16M4A3-M PS is an M4A3-specification carbine with permanently installed pinned stock, 16-inch cold-hammer-forged chrome-lined barrel, and M4 profile. Intended for states with assault weapons restrictions that prohibit collapsing stocks. The PS suffix indicates the pinned stock compliance configuration. Type: Rifle Action: Semi-Automatic Caliber: 5.56x45mm Capacity: 30 Year introduced: 2014, USA Weight: 7 oz Overall length: 32.5" Status: Active Intended use: home defense, general purpose, restricted states