SIG Sauer M400 SENTRY 5.56 NATO 16 in ROMEO5 Gen II

The SIG Sauer M400 SENTRY is a semi-automatic modern sporting rifle chambered in .223 REM/5.56 NATO with a 16 in barrel. Built on the M400 SDI platform, this carbine-level AR combines a free‑floating M-LOK handguard and a low-profile gas/medium-length operating system for range use, duty or home defense. The package includes a ROMEO5 Gen II red dot and Foxtrot‑MSR full-size light; the handguard accepts M-LOK accessories and the optic rides on a top Picatinny rail.

Key Specifications

• Caliber / Chambering: .223 REM/5.56 NATO
• Barrel Length: 16 in (standard carbine length)
• Twist Rate: 1:7
• Operating System: Mid-Length Direct Impingement
• Gas System Length: Mid-Length
• Thread Pitch / Muzzle threads: 1/2 in-28 tpi (tapered shoulder)
• Handguard interface: Free‑floating M-LOK
• Overall Length: 36.5 in
• Weight: 8.0 lb
• Finish / coating: Black anodized

The M400 SENTRY ships with an installed ROMEO5 Gen II red dot and a Foxtrot‑MSR full-size light, plus one 30‑round polymer magazine. Provided source data shows one or more spec conflicts — verify details before publication.

For any additional technical details not listed here, reference the manufacturer’s website. Gundalorians… gear up.

*All Suppressors, Silencers, SBR’s, Machine Guns, and any other NFA regulated items require NFA Forms, Fingerprints, and the $0 Tax Stamp. NFA Rules subject to change.