SIG SAUER M400 SDI 5.56mm 16-inch rifle in Moss Green finish

SIG SAUER M400 Sdi 5.56mm 16" Moss Grn

Sig Sauer
UPC:
798681701216
$1,662.69
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Description

The SIG SAUER M400 SDi in Moss Green delivers battle-proven AR-platform performance in a distinctive, tactical finish — built for serious shooters who demand reliability and versatility from their semi-automatic rifle.

  • Chambered in 5.56 NATO / .223 Rem for proven, widely available ammunition
  • 16-inch barrel strikes the ideal balance of velocity and maneuverability
  • Eye-catching Moss Green finish for a unique, field-ready tactical aesthetic
  • 6-position Magpul MOE-SL collapsible/folding stock fits a wide range of shooters
  • Ships with one 30-round polymer magazine for immediate range readiness
  • Optics-ready design with no sights — easily mount your preferred optic system

Who This Is For

The M400 SDi is purpose-built for competitive shooters, home defenders, and AR enthusiasts who want SIG SAUER's renowned engineering paired with a distinctive Moss Green aesthetic. Whether you're running a precision optic at the range or configuring a versatile home-defense platform, this rifle's ergonomic Magpul stock, standard AR controls, and optics-ready upper make it an outstanding foundation for any build or mission profile.

SIG SAUER M400 SDi 5.56mm 16-inch Moss Green semi-automatic rifle left side view

Specifications

BrandSIG SAUER
ModelM400 SDi
SKU / Part NumberRM400-SDI-16B-MSGRN
Caliber.223 Rem / 5.56 NATO
Barrel Length16 inches
Capacity30+1 rounds
FinishMoss Green
StockMagpul MOE-SL 6-Position Collapsible/Folding
SightsNone (optics-ready)
Included Magazine1 × 30-round polymer magazine
ActionSemi-Automatic
PlatformAR-15 Pattern

Frequently Asked Questions

What optics are compatible with the SIG SAUER M400 SDi?

The M400 SDi ships with a standard Picatinny / MIL-STD-1913 rail on the upper receiver, making it compatible with virtually any red dot sight, holographic sight, or magnified scope that uses a standard AR-pattern mount. Popular pairings include the SIG SAUER Romeo series, Trijicon MRO, and Vortex Strikefire — all of which mount directly without adapters.

Can I use .223 Remington ammunition in this rifle, or does it require 5.56 NATO?

The M400 SDi is chambered for 5.56 NATO, which means it safely accepts both 5.56 NATO and .223 Remington ammunition. 5.56 NATO chambers are cut to slightly more generous tolerances than dedicated .223 chambers, so you can run either cartridge without concern. Note that a rifle marked ".223 Rem only" should not be used with 5.56 NATO loads, but the reverse is perfectly safe.

California buyers: what should I know before purchasing this rifle?

Because Goodland Guns is located in California, this rifle must comply with California's Assault Weapons Control Act (AWCA). Features such as the folding/collapsible stock may require a fixed-magazine configuration or other compliance modifications to be transferred legally within the state. Please contact Goodland Guns directly to confirm the exact compliance configuration available for California residents before completing your purchase.