The Sig Sauer M400 SDI is an AR-pattern semi-automatic rifle chambered in 5.56 NATO with a 16-inch barrel. It has a Cerakote Moss Green finish, a Magpul SL stock, and a factory-installed 2-stage Matchlite Duo trigger. The rifle ships with a 30-round magazine. 
 

Key Specifications 

• Brand: Sig Sauer 
• Model: M400 SDI 
• Caliber: 5.56 NATO 
• Action: Semi Auto 
• Capacity: 30+1 
• Barrel Length: 16 in 
• Color/Finish: Moss Green (Cerakote) 
   

Detailed Features 

• 16-inch threaded barrel 
• Cerakote Moss Green finish 
• Magpul SL stock 
• Factory-installed 2-stage Matchlite Duo trigger 
• Optics-ready configuration with 30-round magazine

The M400 SDI in Moss Green draws the same buyer profile as other SDI variants: owners who want a factory AR with a quality trigger without doing the work themselves. The Moss Green Cerakote is seen as a more subdued color option, and some owners specifically choose it over FDE for use in terrain where green tones blend better.

The 2-stage Matchlite Duo trigger is the recurring point of praise. Owners consistently describe the break as clean and the reset as short relative to mil-spec alternatives, and several note it as the primary reason they chose this rifle over an otherwise similar configuration.

Value opinions split predictably: some owners consider the complete package a fair deal; others note the same trigger performance is achievable for less if you build your own rifle or buy a standard model and upgrade. The Magpul SL stock is generally well-liked for stability, though some owners swap to an adjustable option for different shooting positions.