Benelli rifles are masterworks of curves and angles never before imagined possible by firearms designers. In its general outline, the Benelli R1 rifle resembles the legendary Benelli Super Black Eagle. The steel upper receiver of a Benelli rifle is fixed to the cryogenically-treated barrel, which is free-floated in the fore-end. The lower receiver is made of anodized, lightweight aluminum. The buttstock and fluted fore-end are made of select walnut, and are ergonomically designed with a unique and distinctive recoil pad that is thickest where recoil is concentrated. The auto-regulating gas-operated (ARGO) system proven in the M4 military shotgun has been adapted to centerfire rifle cartridges, working with a three-lugged rotary bolt. The gas cylinder of Benelli rifles is located well back for a short operating rod and reduced recoiling mass. All Benelli R1 rifle barrels are cryogenically-treated to remove stresses induced during hammer-forging. With internal stresses eliminated, barrels expand evenly and predictably from the heat of firing. This helps ensure the superb accuracy for which Benelli R1 Rifles are known.