The Sig Sauer M400 SWAT is an AR-pattern semi-automatic pistol chambered in 5.56 NATO with an 11.5-inch barrel. It is configured as a pistol with a stabilizing brace and is offered in black. One bundle variant includes an EOTECH optic. 
 

Key Specifications 

• Brand: Sig Sauer 
• Model: M400 SWAT 
• Caliber: 5.56 NATO / .223 Rem 
• Action: Semi Auto 
• Capacity: 10+1 
• Barrel Length: 11.5 in 
• Color/Finish: Black 
   

Detailed Features 

• 11.5-inch barrel in a pistol configuration with stabilizing brace 
• Chambered in 5.56 NATO, also accepts .223 Rem 
• SWAT-designated AR-pattern build 
• Available with EOTECH optic package 
• 10+1 capacity on California-compliant configurations; standard magazines may differ by jurisdiction

Owners of the M400 SWAT pistol appreciate the compact 11.5-inch package for home use and range work. The Sig build quality draws consistent praise, and the brace makes the short-barreled format more manageable for extended shooting sessions. Adding the EOTECH bundle resonates well with buyers who want a ready-to-run setup out of the box.

The 11.5-inch barrel and 5.56 NATO combination produces a noticeable muzzle blast at indoor ranges, which is the most common complaint. Owners recommend a suppressor or muzzle device upgrade. Regulatory considerations for the brace configuration also generate questions in ownership forums.

Value relative to Sig's pricing is debated. Some owners feel the M400 SWAT commands a premium over comparable AR-pattern pistols without a proportional fit-and-finish advantage, though the trigger draws mostly positive feedback.