SIG Sauer M400 Sentry Rifle, 16-Inch Barrel

Description

The M400 Sentry is Sig Sauer’s ready-to-run AR-platform rifle built for the shooter who wants a capable, optics-paired package without sourcing components separately. It ships with the Romeo5 Gen II red dot and the Foxtrot-MSR weapon light already mounted, which means the rifle is zeroed and ready to use the moment it leaves the box rather than requiring the buyer to sort compatibility between optic footprints, mount heights, and rail sections.

The 1-in-7-inch twist rate is the faster end of the common AR-15 spectrum. That rate stabilizes heavier projectiles reliably — bullets in the 62- to 77-grain range — while still handling standard 55-grain ammunition without issue. Shooters who run a wide variety of loads can do so without concern, but the twist is particularly well-matched to the heavier 5.56 NATO military-spec loads or premium 62-grain bonded hunting bullets if the rifle is used in the field.

The ambidextrous safety selector is a functional choice rather than a cosmetic one. Left-handed shooters can run the rifle without aftermarket modification, and right-handed shooters operating under gloves or in awkward positions gain a second engagement point on the opposite side of the receiver.

The rifle comes with a single 30-round magazine, giving the buyer one reliable source of ammunition feed before adding additional magazines. No backup iron sights are included in the package, so a shooter who wants a secondary aiming solution beyond the Romeo5 should plan to add them. The Romeo5 Gen II is the primary sighting system as delivered.

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.