The Beretta Rx4 is a rifle eveloped and manufactured by the Beretta Holding of Italy. The action is a Gas-operated, rotating bolt, using the Auto-Regulated Gas-Operated system patented by Benelli. The rifle uses STANAG magazines and can feature either a fixed stock or an adjustable stock. The rifle is in the same "family" as the Beretta Px4 Storm pistol and the Cx4 Storm Carbine, but doesn't shares working systems or parts with any of the above. This weapon operates only in semi-automatic mode, and no selective-fire or otherwise full-automatic version of the Rx4 carbine planned. Beretta is already developing a completely different new-generation assault rifle called the ARX-160. The Rx4 Storm is thus not currently in any military use, as it has not been intended to be, albeit one of its variants (the 12,5-inch barrel "Tactical" version with pistol grip and 5-positions telescopic stock) has been intended primarily as a "patrol carbine" for Police organizations and private security operators.