SIG SAUER M400 Rose 5.56mm 16" Romeo 5x2
$1,453.69
SIG SAUER M400 Sdi 5.56mm 16" Fde 30+1
Sig Sauer
$1,662.69
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Sig Sauer
SIG SAUER M400 Sdi 5.56mm 16" Fde 30+1
The SIG SAUER M400 SDi in Flat Dark Earth is a purpose-built, semi-automatic rifle that blends battlefield-proven AR-platform reliability with modern, mission-ready features — all chambered in the versatile 5.56mm NATO/.223 Rem cartridge.
- Chambered in 5.56 NATO/.223 Rem for proven, widely available ammunition
- 16" barrel delivers optimal velocity and accuracy for mid-range engagements
- Flat Dark Earth finish provides a tactical, corrosion-resistant exterior coating
- Magpul BSL pistol brace with collapsible/folding stock for versatile configurations
- Includes one 30-round polymer magazine for high-capacity, ready-to-run performance
- No-frills iron sight setup leaves the optics rail open for your preferred glass
Who This Is For
The SIG SAUER M400 SDi is ideal for experienced AR-platform shooters, home defenders, and range enthusiasts who demand a reliable, feature-rich rifle straight out of the box. Its folding/collapsible Magpul BSL brace and FDE finish make it especially attractive to tactical shooters and collectors who want a versatile, hard-use carbine without compromise.
Specifications
| Model | M400 SDi |
|---|---|
| SKU / Part Number | RM400-SDI-16B-FDE |
| Caliber | .223 Rem / 5.56 NATO |
| Barrel Length | 16" |
| Capacity | 30+1 |
| Finish | Flat Dark Earth (FDE) |
| Stock / Brace | Magpul BSL Pistol Brace (Collapsible / Folding) |
| Sights | None (optics-ready rail) |
| Magazine Included | 1 × 30-Round Polymer Magazine |
| Action | Semi-Automatic |
| Brand | SIG SAUER |
Frequently Asked Questions
Can I use both .223 Remington and 5.56 NATO ammunition in the M400 SDi?
Yes. The SIG SAUER M400 SDi is rated for both .223 Remington and 5.56 NATO ammunition. The chamber is designed to safely handle the higher pressure of 5.56 NATO rounds while remaining fully compatible with the more common .223 Rem loads, giving you maximum flexibility at the range or in the field.
Does the M400 SDi come with optics, or do I need to purchase them separately?
The M400 SDi ships without iron sights or optics, but it features a full-length Picatinny-style top rail that accepts a wide variety of red dots, holographic sights, magnified scopes, and BUIS (back-up iron sights). This lets you customize your optic setup to match your specific shooting needs and budget.
Is the included 30-round magazine compliant for use in California?
California law restricts detachable magazines to a maximum capacity of 10 rounds for most configurations. The M400 SDi ships with a 30-round polymer magazine; however, California residents are subject to the state's magazine capacity laws. We strongly recommend consulting current California DOJ guidelines or speaking with our staff at Goodland Guns before purchase to ensure full compliance with local regulations.