The Beretta Cx4 Storm is a pistol-caliber carbine aimed at sporting, personal defense and law enforcement. Seven different models accept full-size Beretta magazines from the 92/96, Cougar, and Px4 series pistols in 9mm Luger, .40 S&W and .45 ACP. The cold-forged 16.6-inch (422 mm) barrel is chrome-lined to improve durability and corrosion resistance.
The Cx4 Storm was developed to be used in conjunction with other Beretta semi-automatic pistols. For example, the magazines for the Beretta 92FS chambered in 9 mm can be used in the Cx4 (also chambered in 9 mm). This aids in a smaller loadout — no longer needing to carry separate magazines for the rifle and handgun — and adds redundancy, allowing a person to carry more ammunition without adding weight. Using the non-Beretta Storm Magazines require a two piece kit (not included with rifle). The pieces consist of the following
The 9mm Luger and .40 S&W magazines of the Px4 require the C5C620 insert and C89210 release button. Every caliber can be purchased with CX4 magazines that only fit the CX4. The .45ACP only comes in this way.
The CX4 Storm includes a Picatinny rail that can be extended under the barrel by pushing in the sling button and pulling the rail out by a thumb tab. Each Storm also includes 1 side rail with two mounting screws, a second can be purchased along with a bottom rail from the manufacturer. The countoured bottom rail is designed to attach under the two side rails. A top rail can also be purchased and installed with a tool that comes with the carbine. Three screws and nuts attach it to the top of the carbine using a pre drilled hole that exists allowing the user to use the rail as a template to tap two other holes hidden under a thin membrane of plastic. The correct size drill bit needed for attaching the top rail is not included with the rifle or the top rail kit and has to be purchased separately. A maximum of five picatinny rails can be utilized using Beretta accessory kits, or the user can use the two present at purchase to attach a number of optics, grips, lights, lasers bipods etc. This firearm was designed to be very adaptable to customization.
In addition to being able to customize the Cx4 with accessories, it is one of only a few firearms with the ability to switch the safety, ejection port, and magazine release to the left side of the weapon to accommodate left handed shooters.