SIG M400 XSERIES 556NATO 16″ 30RD

Description

The M400 X-Series SDI is built for shooters who want a serious, ready-to-run AR-15 without spending time sourcing and fitting individual upgrades. It suits the defensive shooter, the practical competitor, or the hog hunter who needs a rifle that handles reliably from first round to last without a break-in period or a parts list.

The mid-length gas system — longer than carbine-length — spaces the gas port farther from the chamber, which reduces port pressure at the moment the bolt unlocks. The practical result is a softer, more rearward recoil impulse and less wear on the bolt carrier group over a high round count. Combined with a free-floating M-LOK handguard that uses a clamp system designed to resist deflection under accessory loads, the platform gives you a stable foundation whether you’re running a light, a pressure switch, or a bipod.

The 1:7-inch twist rate stabilizes heavier projectiles effectively — think 69- to 77-grain match or hunting bullets — making it a good match for longer-range precision work or medium game. Lighter loads in the 55-grain range still function fine; they simply won’t extract the last percentage of accuracy that the twist is capable of delivering. The threaded muzzle, cut at 1/2″-28 tpi, accepts the broadest range of standard 5.56 muzzle devices.

Ambidextrous controls — bolt catch and release, selector, charging handle, and magazine release — are all factory fitted, not retrofitted afterthoughts. The two-stage SIG Flat Blade Match trigger gives a defined break that supports consistent shot execution, particularly in situations where grip angle or position isn’t ideal. The Magpul SL telescoping stock keeps the package compact without adding unnecessary bulk. One 30-round magazine is included.

Shipping and availability: This item cannot be shipped directly to California, Rhode Island and Washington. Check your state and local requirements before ordering. This item must ship to a licensed FFL dealer for transfer.