The Sig Sauer M400 Forge is an AR-pattern semi-automatic rifle chambered in 5.56 NATO with a 16-inch barrel and 10+1 capacity. This variant is California-compliant and includes a ROMEO-MSR Gen II red dot, M-Lok handguard, Picatinny rail, black anodized alloy receiver, Magpul MOE stock, and Shark Fin grip. 
 

Key Specifications 

• Brand: Sig Sauer 
• Model: M400 Forge 
• Caliber: 5.56 NATO 
• Action: Semi Auto 
• Capacity: 10+1 
• Barrel Length: 16 in 
• Color/Finish: Black 
   

Detailed Features 

• California-compliant configuration with Shark Fin grip 
• Ships with ROMEO-MSR Gen II red dot sight 
• Black anodized alloy receiver with Picatinny rail 
• M-Lok handguard for accessory mounting 
• Magpul MOE Black Polymer stock

Owners in restricted states pick up the CA-compliant M400 Forge because it checks the required boxes while still coming with the ROMEO-MSR Gen II red dot included. Most appreciate not having to hunt for a separate compliant configuration on top of sourcing glass.

The Shark Fin grip that makes this CA-compliant draws the most discussion. Shooters accustomed to traditional pistol grips find it awkward at first and report a brief adjustment period. Those who spend time with it often find it usable for range sessions, but swapping to a standard grip (where legally permitted) remains a common first modification.

The M400 Forge platform itself is well-regarded for reliability and build quality. The Magpul MOE stock and M-Lok handguard are familiar components that most owners are comfortable with, and the rifle is seen as a capable baseline for those who want to add accessories over time.