The Fierce Mayhem FX is an inertia-driven semi-automatic shotgun chambered in 12 gauge with a 3.5" chamber and a camouflage finish, built for hunters who want reliable cycling with heavier loads and a few practical ergonomic improvements over standard designs. 
 

Key Specifications 

• Model: Mayhem FX 
• Caliber: 12 Gauge 
• Action: Semi-Auto 
• Chamber: 3.5" 
• Barrel Length: 28" 
• Capacity: 5+1 rounds 
• Weight: 7.70 lbs 
• Sights: HiViz Fiber Optic Front 
• Stock: Fixed with Max-Grip 
• Safety: Crossbolt 
   

Detailed Features 

The inertia-driven system is mechanically simple, which tends to translate to consistent cycling and less sensitivity to load variations. The Fierce KO extended choke tube is designed to tighten and improve shot patterns, which matters for hunters working at longer ranges. 
 
The oversized bolt handle and release button make cycling and loading easier with gloved hands -- a detail that gets overlooked on many shotguns but is genuinely useful in cold weather. The extra-large trigger guard works the same way. Grip-maxx contact points and the slim forearm profile give you a secure hold without adding bulk. The Limbsaver recoil pad absorbs a meaningful amount of the impulse from heavier loads, especially with 3.5" shells where recoil is substantial. At 7.70 lbs it's on the heavier side, but the added weight helps manage that recoil.

Discussions about the Fierce Mayhem FX Gen 1 tend to be positive about the design and field performance. The camouflage finish is appreciated for concealment in various environments. The inertia action gets consistent praise for its smooth operation and reliability.

Field performance in terms of accuracy and recoil management is a frequent highlight. Owners also mention good experiences with customer service and warranty support.

On the critical side, some users question long-term durability under harsh or high-volume use, and a handful report issues cycling specific ammunition types. Aftermarket accessories are harder to find for this model than for more established brands. Some buyers feel the price is high relative to comparable semi-autos on the market.