Sig Sauer M400 SDI XSeries 5.56 16" - AR-15 Rifle

The Sig Sauer M400 SDI XSeries 5.56 16" delivers everything an AR-15 should — dependable 5.56 function, quality construction, and straightforward ergonomics — without asking you to pay for features you don't need.

Built as a semi-automatic AR-15 rifle around 5.56 and a direct impingement system, the Sig Sauer M400 SDI XSeries 5.56 16" delivers a proven AR-15 experience from first round to last.

Reliable Function: A proven direct impingement operating system cycles a wide range of 5.56 ammunition reliably — the foundation of any dependable AR-15.

Practical Barrel Length: The 16" barrel strikes a practical balance between velocity, maneuverability, and overall weight — a versatile choice for both defensive and recreational use.

Full Aftermarket Compatibility: Standard AR-15 architecture means the full range of aftermarket components, optics, and accessories are available — configure this rifle exactly how you want it.

Durable Construction: Quality materials and a durable finish ensure this platform holds up under regular range use and long-term storage without degrading function or accuracy.

• Caliber: 5.56
• Barrel Length: 16"
• Gas System: Direct Impingement
• Handguard: Picatinny Quad Rail
• Muzzle Threading: 1/2x28
• Magazine Capacity: 30-Round
• Finish: Type III Hardcoat Anodized
• Origin: Made in the USA

Drop-in compatible with mil-spec AR-15 lower receivers. Takes standard STANAG magazines chambered in 5.56 and works with the full range of AR-15 accessories and aftermarket upgrades.

Type III Hardcoat Anodized over 7075 aluminum construction gives this AR-15 rifle solid corrosion resistance and a durable surface that holds up across a wide range of storage and operating conditions.

Practical for home defense, recreational range use, and entry-level competition. Suits both first-time AR-15 buyers and experienced shooters looking for a dependable utility rifle.

SIG SAUER is trusted by the U.S. military and law enforcement agencies worldwide. Their AR-15 lineup delivers the same premium quality and engineering that earned SIG that trust. Made in the USA.