The Fierce Firearms Mayhem FX is a semi-automatic 12 GA shotgun with a 28-inch barrel and a 3.5-inch chamber. Capacity is 5+1 rounds, weight is 7.70 lbs. Natural camouflage finish. HiViz Fiber Optic Front sight. Fixed stock with Max-Grip texture. Crossbolt safety. Inertia-driven action. Oversized bolt handle and release. XL/oversized trigger guard accommodates gloves. Grip-maxx contact points on stock and forend. Ships with Fierce KO Extended choke. 
 

Key Specifications 

• Model: Mayhem FX 
• Caliber: 12 GA 
• Action: Semi-Auto 
• Capacity: 5+1 rounds 
• Barrel Length: 28 inches 
• Weight: 7.70 lbs 
• Chamber Size: 3.5 inches 
• Sights: HiViz Fiber Optic Front Sight 
• Stock Description: Fixed with Max-Grip 
• Safety Mechanism: Crossbolt Safety 
• Finish Color: Natural Camouflage 
   

Features 

 
The 3.5-inch chamber handles the full range of 12-gauge loads including magnum waterfowl shells. The inertia-driven action is mechanically simpler than gas systems and tends to be less affected by fouling in the field. At 7.70 lbs the gun is on the heavier side, which absorbs recoil but adds carry weight. The oversized bolt handle and release are practical with gloved hands in cold-weather hunting. The XL trigger guard accommodates heavy gloves. Grip-maxx contact points improve hold in wet conditions. HiViz fiber optic front sight provides good visibility. The Fierce KO Extended choke is designed to tighten patterns for longer shots.

The Mayhem FX draws favorable feedback for its cycling reliability with both light and heavy loads, and the inertia drive system is generally trusted for field use. Build quality comments are positive -- the gun is described as feeling solid and well-finished. The 28-inch barrel and 3.5-inch chamber combination is seen as a capable waterfowl and versatile hunting setup.

At 7.70 lbs the weight draws criticism from buyers who prioritize a light carry gun, particularly on long hunts. Felt recoil with heavier magnum loads is noted as more pronounced than competing semi-autos at similar weights. The price point is discussed as a barrier for some buyers. Aftermarket accessories and parts availability is mentioned as limited compared to more established platforms. Overall the gun holds a niche following among serious waterfowl hunters who value the 3.5-inch capability and inertia reliability.