Gforce Arms GF12HMRB MKX3 12-Hammer 12 Gauge Semi-Auto 3" 5+1 18.50" Black Steel Barrel, Black Anodized Aluminum Receiver, Fixed Synthetic Stock

The Gforce Arms MKX3 12-Hammer is a 12 gauge semi-auto shotgun built for shooters who want a compact, no-nonsense platform for home defense, sport shooting, or tactical training. With an 18.50-inch barrel and an overall length of 37.5 inches, it's maneuverable in tight spaces without sacrificing the handling characteristics serious shooters demand. The gas-operated system cycles both 2.75-inch and 3-inch shells, giving you flexibility in ammunition selection and keeping your options open whether you're running target loads or full-power buckshot.

Built on a black anodized aluminum receiver paired with a 4140 steel barrel finished in black, the MKX3 delivers a tough, corrosion-resistant platform that handles hard use. The fixed synthetic stock keeps weight down—a svelte 8.2 pounds—and the 14-inch length of pull accommodates a wide range of shooter builds. Recoil management comes courtesy of a rubber recoil pad, which softens the impulse and encourages faster follow-up shots. A pop-up polymer sight comes mounted, and the aluminum alloy forend won't flex or twist during aggressive handling.

The shotgun arrives with one magazine and accepts MKA1919-pattern magazines for easy reloads. Choke compatibility follows the Benelli Mobil standard, and the gun ships with cylinder, modified, and full chokes so you can dial in your pattern for the mission at hand. The MKX3 operates smoothly with ammunition rated at 1200 FPS, and a limited lifetime warranty backs your investment.

Key Features

• Gas-operated semi-auto action cycles 2.75" and 3" shells reliably
• Compact 18.50" barrel—quick to handle in confined spaces
• Lightweight aluminum receiver (8.2 lbs total) reduces fatigue during extended sessions
• Black anodized receiver and steel barrel resist corrosion
• Fixed synthetic stock and aluminum forend—durable and low-maintenance
• Pop-up polymer sight included; easy to co-witness with optics
• Benelli Mobil choke threads; three chokes included (cylinder, modified, full)
• Rubber recoil pad absorbs impulse and aids target recovery
• One magazine included; compatible with MKA1919-pattern magazines
• Limited lifetime warranty

Specifications

Frequently Asked Questions

Will the MKX3 reliably cycle both 2.75 and 3-inch shells?

Yes. The gas-operated system is designed to cycle both 2.75-inch and 3-inch ammunition, giving you flexibility in your ammunition selection.

What chokes come with the shotgun?

The MKX3 ships with three chokes—cylinder, modified, and full—all compatible with Benelli Mobil choke threads. This gives you options to adjust your shot pattern for different distances and applications.

Can I use optics or other sights with the pop-up sight?

The pop-up polymer sight is included and mounted on the gun. The design allows for co-witnessing with optics mounted on the receiver or handguard, though you'll want to verify clearance with your specific setup.

What magazines work with this shotgun?

The MKX3 uses MKA1919-pattern magazines. One magazine is included with the gun, and additional MKA1919-compatible magazines can be purchased separately for faster reloads.