Sig M400 Sdi 556nato 16" Blk Romeo5

The SIG Sauer M400 SDI 5.56 NATO 16-inch Rifle with Romeo5 Red Dot is a mid-length direct impingement carbine engineered for duty, training, and home defense applications. Built on the proven M400 platform, this 5.56 NATO rifle combines a threaded 16-inch barrel with a factory-installed SIG Romeo5 red dot sight and integrated Foxtrot MSR tactical light—delivering a complete fighting system ready for immediate deployment from the bench or the field.

The 16-inch barrel length balances velocity retention with compact handling, critical for vehicle-based operations, building clearance, and close-quarters engagement. The threaded muzzle enables attachment of sound suppressors, muzzle devices, or flash mitigation hardware without gunsmithing. Cerakote finish provides enhanced corrosion resistance compared to standard mil-spec parkerizing, essential for prolonged storage, salt-air environments, and high-round-count training cycles. The rifle ships with a 30-round magazine and feeds standard 5.56 NATO and .223 Remington ammunition, ensuring compatibility across commercial and military supply chains.

This configuration suits law enforcement patrol units, military reserve training, civilian tactical training, and serious sport shooters who demand professional-grade optics and illumination without separate procurement. The Romeo5 red dot offers quick target acquisition and holds zero across the effective 5.56 engagement envelope, while the Foxtrot MSR light—integral to modern duty carbines—eliminates the need for secondary mounting solutions. At 9.69 pounds, the complete system manages recoil impulse while remaining mobile for extended operations.