The Benelli M4 EXT in H2O Titanium Cerakote is the combat-proven M4 built for the places that eat shotguns alive. Salt air, boat decks, humid coastal storage, and hard-use marine environments are exactly what the H2O treatment exists for. Add the EXT upgrades — 7+1 capacity, a 5-position telescoping stock, and an oversized bolt release — and you get Benelli's flagship fighting shotgun in its most corrosion-resistant configuration. Benelli item number 11789, UPC 650350117899.

H2O: Built Where Corrosion Wins

The H2O designation is a reference to water, and it means what it says. Receiver and barrel are finished in Titanium Cerakote, a ceramic-based coating chosen specifically for its salt-spray and corrosion performance — Cerakote's published testing puts the finish through thousands of hours of continuous salt-fog exposure without corrosion. The result is a distinctive light gray-titanium gun that shrugs off the humidity, spray, and sweat that pit and rust conventional finishes. If the shotgun lives on a boat, in a coastal safe, or in a patrol vehicle in a wet climate, this is the M4 to buy.

A.R.G.O. — Unfailing By Design

At the heart of the M4 EXT is Benelli's Auto-Regulating Gas-Operated (A.R.G.O.) system: dual short-stroke gas pistons positioned close to the chamber, engineered to run clean, cycle anything, and keep firing through dirt, heat, and punishing round counts. The system is self-cleaning and low-maintenance with nothing to tune — it self-regulates across 2¾" and 3" loads, from reduced-recoil buckshot to full-power slugs. A.R.G.O. is the reason the M4 has held its reputation for decades in military, law enforcement, and hard civilian service.

More Capacity. Finally.

The single most requested change to the M4 is now standard. The M4 EXT ships with an extended magazine tube delivering 7+1 capacity — built to carry more so you can push harder. Whether clearing rooms or defending ground, extended capacity means fewer reloads and no hesitation under pressure. The rugged oversized bolt release makes those reloads faster and more certain with gloves, cold hands, or under stress.

Five Positions. Full Control.

The 5-position telescoping stock adjusts length of pull from 9¼" to 14" without tools, so the gun fits correctly over body armor, a float coat, or a bare shoulder. Paired with the M4's pistol grip, it delivers rapid adjustment, superior control, and the rugged reliability the platform demands. A flush-cup QD sling mount is embedded directly in the stock for fast, snag-free sling attachment.

Sights, Optics, and Compliance

Factory ghost-ring sights provide fast, forgiving alignment at defensive distances, and an included Picatinny rail on a drilled-and-tapped receiver accepts red dots and magnified optics. The M4 EXT ships with a Modified choke tube for improved pellet density and consistent mid-range performance straight out of the box. The M4 EXT is 922(r) compliant.

Benelli M4 EXT H2O 11789 Specifications

Who This Shotgun Is For

The M4 EXT H2O is for buyers whose environment is the threat as much as anything else: coastal and Gulf homeowners, boat and marine security, waterfowl-country law enforcement, and anyone who has watched a blued gun rust in a humid safe. It's equally at home as a home defense shotgun, a patrol or entry shotgun, or a duty-grade training gun that will run hard for years without a rebuild — it just does it in the one finish built to survive salt.

What's in the Box

• Benelli M4 EXT H2O shotgun, Titanium Cerakote, 18.5" barrel
• Modified choke tube installed
• Picatinny rail
• Owner's manual and Benelli case (packaging per current factory configuration)

Frequently Asked Questions

What does "H2O" actually mean on a Benelli?

H2O is Benelli's designation for its corrosion-resistant configuration, named for water. On the current M4 EXT it means a Titanium Cerakote finish on the receiver and barrel, selected for salt-spray and corrosion performance in marine and high-humidity environments.

How is the M4 EXT different from the standard M4 Tactical?

Three changes: 7+1 capacity instead of 5+1, a 5-position telescoping stock (9¼"–14" LOP), and an oversized bolt release. Same 18.5" barrel, same A.R.G.O. action, same ghost-ring sights.

Is the M4 EXT 922(r) compliant?

Yes. Benelli lists the M4 EXT as 922(r) compliant as delivered — a meaningful advantage over building 7+1 capacity from aftermarket parts.

Can I mount an optic?

Yes. A Picatinny rail is included and the receiver is drilled and tapped, so red dots and LPVOs mount directly with the correct footprint or mount.