The Sig Sauer M400-SENTRY SDI combines the M400-SDI platform with factory-installed ROMEO5 Gen II red dot and Foxtrot-MSR full-size light to deliver a ready-to-use AR-style rifle. Configured around a 16 inch barrel and mid-length gas system, the rifle includes a free-floating M-LOK handguard, a vertical foregrip and one 30-round polymer magazine. This SENTRY combo is suited to range use, training, and personal security applications where a complete, out-of-the-box setup is preferred.
Key Specifications
- The caliber is .223 Rem/5.56 NATO.
- The barrel length is 16 inches.
- The magazine capacity is 30 rounds.
- The installed optic is the ROMEO5 Gen II red dot.
- The illumination package is the Foxtrot-MSR Full Size light (1250 lumens).
- The stock is a 6-position Magpul MOE-SL.
- The trigger is a SIG 2-Stage Matchlite Duo.
- The twist rate is 1:7.
- The operating system is mid-length direct impingement.
- The handguard is a free-floating M-LOK and the rifle includes a vertical foregrip.
Built on SIG Sauer’s M400-SDI architecture, the M400-SENTRY provides a straightforward, fully featured package for shooters who want a factory-configured rifle with sighting and illumination already in place. Its combination of proven components and ergonomic controls makes it practical for extended range sessions, skill development, and responsible personal security use.
Product information is supplied by the manufacturer and/or distributor and may be automatically formatted or enhanced using AI for clarity and consistency. While we strive for accuracy, specifications, features, and included items may change without notice. Always verify details using the manufacturer’s official documentation and the information shown on this product page before purchase or use.
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