Genesis Arms Gen-12 SBM 12 Gauge Firearm 10.5" Barrel - 5 Rd

Genesis Arms Gen-12 SBM 12 Gauge Firearm 10.5" Barrel - 5 Rd

The Genesis Arms Gen-12 10.5" takes the proven ergonomics and modularity of the AR platform and scales them up to handle the raw authority of 12 gauge ammunition — delivering a semi-automatic, magazine-fed shotgun that operates, handles, and accessorizes like the AR you already know, with the terminal performance of a platform in a class of its own.

Classified as an Other Firearm and built around Genesis Arms' purpose-engineered short recoil operating system, the Gen-12 10.5" manages the considerable pressures of 12 gauge cycling within a compact, AR-pattern configuration that no traditional shotgun design can replicate. The 10.5" barrel chambers both 2¾" and 3" shells, giving shooters the flexibility to run everything from standard birdshot and buckshot to full 3-inch magnum loads — while the factory-installed blast can with crown muzzle device and 1.375-24 threaded muzzle keep the platform ready for additional muzzle accessories and choke options right out of the box.

The free-float M-LOK handguard with a full-length Picatinny top rail puts optics, red dots, and magnified sights directly over the bore in a rigid, zero-flex mounting solution, while M-LOK slots at 3, 6, and 9 o'clock keep lights, lasers, and foregrips exactly where the shooter needs them. A GEN1 DPMS .308-patterned lower with mil-spec buffer tube and 3.8 oz .308 short carbine buffer keeps the recoil system tuned for reliable cycling across the Gen-12's supported ammunition spectrum, and the Hogue rubberized grip ensures positive purchase through every round — whether you're running light target loads or full-power 3-inch magnums.

AR-Pattern 12 Gauge Platform:
Built on a GEN1 DPMS .308-patterned lower and engineered around familiar AR ergonomics and controls, the Gen-12 10.5" brings AR-platform intuition to 12 gauge capability.

Short Recoil Operating System:
Genesis Arms' purpose-engineered short recoil system is specifically designed to manage the substantial gas pressures of 12 gauge ammunition within a compact AR-pattern configuration.

10.5" Compact Barrel:
Chambered for both 2¾" and 3" 12 gauge shells gives shooters the flexibility to run the full spectrum of 12 gauge ammunition.

Free-Float M-LOK Handguard:
The free-float design eliminates barrel contact pressure for consistent barrel harmonics, while the full-length Picatinny top rail delivers a rigid, uninterrupted optics mounting surface directly over the bore.

Mil-Spec Buffer Tube with .308 Short Carbine Buffer:
The mil-spec buffer tube and purpose-weighted 3.8 oz .308 short carbine buffer are specifically tuned to the Gen-12's short recoil operating system.

GEN1 DPMS .308-Patterned Lower Receiver
Brings the familiar control layout and ergonomic profile of the AR platform to a 12 gauge configuration, enabling intuitive, stress-free operation.

Right-Side Charging Knob
An intuitive right-side charging knob provides positive, reliable chambering and manipulation in a control position that integrates naturally with the AR-pattern platform's overall ergonomic layout.

Specifications

• Gauge: 12 Gauge
• Action: Semi-Automatic, Short Recoil Operated
• Chamber: 2¾" and 3"
• Barrel Length: 10.5 Inches
• Muzzle Thread: 1.375-24
• Muzzle Device: Factory Blast Can with Crown Muzzle Device
• Handguard: Free-Float with M-LOK® Slots — 3, 6, and 9 O'Clock
• Top Rail: Full-Length Picatinny
• Lower Pattern: GEN1 DPMS .308 Pattern
• Buffer Tube: Mil-Spec
• Buffer: .308 Short Carbine — 3.8 oz
• Trigger: Mil-Spec AR Trigger
• Grip: Hogue Rubberized Pistol Grip
• Charging Handle: Right-Side Charging Knob
• Capacity: 5 Rounds
• Included in Box: (1) 5-Round Magazine, Soft Case