Beretta Mx4 Storm

Lore & Background

The Beretta Mx4 Storm is the submachine gun variant of the Cx4 Storm, a semi-automatic pistol-calibre carbine. Both firearms share a common design, including a Picatinny rail on top of the receiver for mounting modern optics and a tri-rail adapter for attaching flashlights, laser sights, grips, and other accessories. The Mx4 also features ambidextrous controls, allowing the fire selector, charging handle, ejection port, and magazine release to be switched to the left side.

The Mx4 Storm was adopted by the Italian Navy, which ordered 90 units in 2013 for delivery in 2014, with a second order placed in 2017. It has also been procured for use by paramilitary forces of India. The Mx4's magazine system is shared with the Beretta 92 pistol series, allowing users to carry one type of magazine for two types of firearms.

Reader's Guide

The Beretta Mx4 Storm represents a select-fire evolution of the Cx4 Storm carbine, designed for military and law enforcement use. Its fully automatic capability and 12-inch barrel distinguish it from the semi-automatic Cx4. The Mx4's compatibility with Beretta 92 magazines simplifies logistics for users who already carry Beretta pistols. The Italian Navy's adoption of the Mx4 Storm in 2013 and 2017 demonstrates its acceptance as a service weapon. The Mx4 shares the Cx4's modular accessory system, including Picatinny and tri-rail mounts, and its ambidextrous controls. While the Cx4 Storm faced legal restrictions in Canada following the 2006 Dawson College shooting—ultimately being classified as prohibited in 2020—the Mx4 Storm's primary market has been military and police forces outside Canada. Its use by Indian paramilitary forces and the Italian Navy underscores its role as a compact, automatic personal defense weapon.

Did You Know?

• The Beretta Mx4 Storm is the fully automatic variant of the Cx4 Storm carbine.
• The Mx4 Storm features a 12-inch barrel and is most commonly seen with a 30-round 9mm magazine.
• The Mx4's magazines are compatible with Beretta 92 pistols.
• The Italian Navy ordered 90 Mx4 Storms in 2013, with a second order placed in 2017.

Magazine Interchangeability and Modular Design

The Beretta Cx4 Storm platform was conceived around a single practical idea: a shooter should not need to carry two different types of ammunition magazines for a sidearm and a carbine. By designing the receiver to accept magazines from the 92/96, 8000 "Cougar," and Px4 pistol families through simple adapter swaps, Beretta let a 9mm 92FS owner feed the same magazine into a matching Cx4. Switching between the three pistol platforms requires replacing just two components—a magwell sleeve and the magazine release button—each sold as a separate part with its own catalog number. The platform chambers 9×19mm Parabellum, .40 S&W, .45 ACP, and 9×21mm, though the .45 ACP variant is restricted to Cougar-series magazines. On the exterior, a Picatinny rail runs along the top of the receiver for optics, while a tri-rail adapter on the handguard accepts flashlights, laser sights, and vertical grips. Beretta also built in ambidextrous options: the fire selector, charging handle, ejection port, and magazine release can all be relocated to the left side, making the carbine genuinely usable by right- and left-handed operators alike.

The Mx4 Storm: Full-Auto Variant

Where the Cx4 Storm fills the semi-automatic carbine niche, the Mx4 Storm steps into the submachine gun role. It is the fully automatic variant of the same platform, capable of sustained full-auto fire that distinguishes it from the semi-auto Cx4. The Mx4 features a 12-inch barrel, giving it a compact profile suited to close-quarters and vehicle-based security roles. In its most common configuration, it is fed by a 30-round 9mm magazine that is directly compatible with Beretta 92-series pistols, preserving the platform's core design philosophy of shared ammunition logistics. Because it inherits the Cx4's receiver architecture, the Mx4 retains the top-mounted Picatinny optics rail, the tri-rail accessory system, and the ambidextrous controls that allow the fire selector, charging handle, ejection port, and magazine release to be moved to the left side. The Mx4 was aimed squarely at the law enforcement and military markets, offering a compact, magazine-compatible automatic weapon that could slot into existing Beretta 92/96 ammunition supply chains without requiring a separate magazine ecosystem.

Global Adoption by Military and Police Forces

The Cx4 and Mx4 Storms found buyers on four continents, reflecting their appeal across a wide range of security and military applications. In 2013, the Italian Navy's Comforsbarc unit ordered ninety Mx4 Storms for a total of €58,606, with delivery scheduled for 2014; a follow-on order arrived in 2017. India procured the carbine for its paramilitary forces, while Libya placed a pre-civil-war order for 1,900 carbines in 2009. Russian police received a large batch of Cx4 carbines fitted with a lengthened 500 mm barrel, a configuration that likely addressed local regulatory or operational requirements. In the United States, the platform served the Albany County, New York Sheriff's Department in .40 S&W, the St. Louis Police Department, and the College of William & Mary Campus Police Department. Venezuela's Comando Nacional de la Guardia del Pueblo, the Bolivarian National Guard, added the carbine to its inventory in 2012. This breadth of adoption—from naval special units to campus police—underscores the platform's versatility across calibers, barrel lengths, and operational contexts.

The Canadian Controversy and Regulatory Aftermath

The Cx4 Storm became entangled in one of Canada's most significant firearms-policy debates after it was the primary weapon used in the 2006 Dawson College shooting in Montreal. The restricted-class carbine had been purchased through legal channels, and the subsequent coroner's inquest recommended that Canada ban all semi-automatic rifles. Paradoxically, the tragedy drove a surge in Cx4 sales among Canadian civilians who wanted to secure the platform before potential restrictions. In 2011, Beretta responded by introducing a non-restricted variant with a 19-inch barrel, making the carbine accessible to a broader segment of the Canadian market without the paperwork associated with restricted firearms. That window of accessibility closed on 1 May 2020, when the Canadian government reclassified every Cx4 Storm variant—regardless of barrel length or caliber—as a prohibited firearm. The episode turned the Cx4 into a symbol in the ongoing Canadian debate over semi-automatic rifle regulation, illustrating how a single incident can reshape an entire product category's legal standing.

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