Beretta Mx4 Storm
- Category
- Submachine Gun
- Barrel
- 312 mm
- Weight, empty
- 2.48 kg
- Introduced
- 2003
About
What it is, and why it matters
The Beretta Mx4 Storm is an Italian select-fire submachine gun developed by Fabbrica d'Armi Pietro Beretta as the military and law enforcement version of the civilian Cx4 Storm semi-automatic carbine. Introduced in 2003, the Mx4 Storm operates on a straightforward blowback principle with a closed-bolt, hammer-fired mechanism, chambered primarily in 9x19mm Parabellum with a .45 ACP variant also available. The weapon features a fiberglass-reinforced technopolymer frame that keeps the weight to just 2.48 kg empty, a 312mm barrel, and an overall length of 647mm with its fixed stock. A key design feature is magazine compatibility with the Beretta 92 pistol series, allowing forces equipped with Beretta sidearms to share ammunition and magazines for improved logistics. The three-position fire selector offers safe, semi-automatic, and full-automatic fire modes at a cyclic rate of approximately 950 rounds per minute. The Mx4 features a full-length MIL-STD-1913 Picatinny rail for optics mounting, fully ambidextrous and reversible controls, and an automatic firing pin block safety integrated with a hammer safety for safe carry. Adopted primarily by the Italian Navy's Special Forces (Comforsbarc), Indian paramilitary forces, and several other nations, the Mx4 Storm provides a lightweight, ergonomic platform for close-quarters operations.
The Mx4 Storm's key selling point is magazine compatibility with the Beretta 92 pistol series, allowing military and police forces to share magazines between their sidearm and submachine gun. The civilian Cx4 Storm semi-auto carbine version has been significantly more commercially successful than the select-fire Mx4.
The Mx4 Storm shares its external design and many components with the civilian Cx4 Storm, but adds a select-fire trigger group and military-grade durability enhancements. The Cx4 Storm has been significantly more commercially successful in civilian markets, while the Mx4 has seen more limited military adoption. The weapon's magazine compatibility with the Beretta 92 series is a significant logistical advantage for military and police forces already equipped with Beretta 92/M9 pistols, as it allows standardization of ammunition magazines across primary and secondary weapons. The Italian Navy ordered 90 units in 2013 with delivery in 2014, followed by a second order in 2017. Libya ordered 1,900 units in 2009, though delivery was complicated by the subsequent Libyan Civil War. The Mx4 Storm features a reciprocating charging handle and the upper and lower receivers are both constructed from fiberglass-reinforced technopolymer, making it one of the lighter submachine guns in its class. The fire selector button is reversible for both right and left-handed operation.
Specification
Everything measured
IdentityWhat it is, who built it and when.
- Manufacturer
- Beretta
- Category
- Submachine Gun
- Country
- Italy
- Status
- In production
- Produced
- 2003
DimensionsAs issued, without a magazine or an optic.
- Barrel
- 312 mm
- Overall length
- 647 mm
- Height
- 189 mm
- Width
- 63 mm
- Sight radius
- 327 mm
- Weight, empty
- 2.48 kg
- Weight, loaded
- 2.95 kg
ActionHow it cycles, what trips it, and what feeds it.
- Action
- Blowback
- Firing mechanism
- Hammer fired
- Trigger
- Select fire
- Capacity
- 30
- Magazine
- Detachable box
MaterialsEach swatch is the material itself, not a colour chosen to stand for it.
- Frame
- Fiberglass reinforced polymer
- Barrel
- Steel
- Stock
- Polymer
- Finish
- Matte black
BallisticsFrom the service cartridge, not a handload.
- Muzzle velocity
- 390 m/s
- Muzzle energy
- 567 J
- Effective range
- 100 m
- Rate of fire
- 950 rpm
Trajectory
What the round does downrange
Solved from the muzzle figures and the bullet. The dashed rule is the effective range on the record, and the crosses are the steps the solver returned.
Features
What it has
What the record lists as fitted, drawn from the catalogue.
Closed bolt firing
Select fire
Fixed stock
Picatinny rail
Ambidextrous controls
Beretta 92 magazine compatible
Iron sights- Polymer construction
Reversible controls
Standing
How it compares
Each figure against the firearms of the same type and cartridge that record it, or of the same type where that cartridge has too few. Positions are read to the nearest tenth.
| Measurement | This firearm | Median | Position |
|---|---|---|---|
| Empty weightAmong 201 9x19mm Parabellum submachine guns | 2.48 kg | 3.18 kg | Lighter than about 80% |
| Overall lengthAmong 200 9x19mm Parabellum submachine guns | 647 mm | 723 mm | Shorter than about 70% |
| Barrel lengthAmong 202 9x19mm Parabellum submachine guns | 312 mm | 213 mm | Longer than about 90% |
| Magazine capacityAmong 204 9x19mm Parabellum submachine guns | 30 | 32 | Holds fewer rounds than about 70% |
Answers
Questions about the Beretta Mx4 Storm
How much does the Beretta Mx4 Storm weigh?
The Beretta Mx4 Storm weighs 2.48 kg (5.47 lb) empty and 2.95 kg (6.50 lb) loaded.
What caliber is the Beretta Mx4 Storm?
The Beretta Mx4 Storm is chambered in 9x19mm Parabellum and .45 ACP.
How many rounds does the Beretta Mx4 Storm hold?
The Beretta Mx4 Storm holds 30 rounds, fed from a detachable box magazine.
How long is the Beretta Mx4 Storm?
The Beretta Mx4 Storm is 647 mm (25.5 in) long overall, with a 312 mm (12.3 in) barrel.
Who makes the Beretta Mx4 Storm?
The Beretta Mx4 Storm is made by Beretta (Italy).
When was the Beretta Mx4 Storm introduced?
The Beretta Mx4 Storm was introduced in 2003.
How does the Beretta Mx4 Storm operate?
The Beretta Mx4 Storm uses a blowback action, and its firing mechanism is hammer fired.
Compatibility
Which parts fit this firearm
Studio
Every part that mounts on this, resolved
Not a list the maker typed out: the answer comes from the mounts this firearm exposes and the interface each part needs, so it stays right when either one changes.
- Every part that mounts on any firearm in the catalogue
- Interface standards, platforms and fit overrides
- The same answers through the API and the MCP server
Requires a signed-in GunSpec account on the Studio plan. The answer is computed per part, so it is not part of the public record.
Provenance
What the record holds
Every figure above was taken from one of these pages. The confidence reflects how much of the record came from a page a claim can be checked against.
In service
- Italian Navy (Comforsbarc)
- 2013
- Indian Border Security Force
- India
- Libyan Armed Forces
- 2009
- Portuguese Armed Forces
- Portugal
- Venezuelan National Guard
- Venezuela
Provenance
Confidence in this record
80%
Stockists
Where to buy
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No shop has listed this firearm yet
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The same record, reached the way a person asks for it rather than the way a program does.
Ask GunSpec
Works with
Point an MCP client at GunSpec and it answers from the catalogue rather than from memory. A free key covers the read tools.
API
The call that returns this record
The same fields, in the same units, from the same endpoint the page reads.
curl --request GET \ --url 'https://api.gunspec.io/v1/firearms/beretta-mx4-storm' \ --header 'X-API-Key: your_key'{ "id": "beretta-mx4-storm", "name": "Beretta Mx4 Storm", "manufacturer": { "id": "beretta", "name": "Beretta", "countryCode": "IT", "foundedYear": 1526, "website": "https://www.beretta.com", "logoUrl": null, "description": null, "status": null, "defunctYear": null, "stateOwned": null, "makesFirearms": null, "parentId": null, "predecessorId": null, "createdAt": "2026-02-11 23:44:38", "updatedAt": "2026-02-18 03:43:40", "version": "8b9fe1893419c995aa99c862828f03dd5729ecd351a2fed53e95d04b9a47918f" }, "category": { "id": "submachine-gun", "name": "Submachine Gun", "description": "Automatic firearms chambered in pistol calibers" }, "country_of_origin": "IT", "year_introduced": 2003, "barrel_length_mm": 312, "weight_empty_g": 2480, "action_type": "blowback"}