The IRS — Integrated Rail System — is Rock River's AR-10 pattern rifle in .308 Winchester built around a full-length Picatinny top rail and modular handguard system. The .308 chambering extends effective range significantly over 5.56 AR-15 platforms, and the IRS handguard allows accessory mounting without gunsmithing. It was designed for hunters and long-range shooters who needed an AR-10 with modern rail real estate. Type: Rifle Action: Semi-Automatic Caliber: .308 Win Capacity: 20 Year introduced: 2010, USA Weight: 170 oz Overall length: 38.25" Status: Active Intended use: Hunting, Target Shooting, Tactical