| Brand | Sig Sauer |
| SKU | RM400SDI16BP |
| UPC | 798681664634 |
| Action | Semi-Automatic |
| Finish | Black |
| Weight | 6.9 pounds |
| Capacity | 30+1 |
| Grip Safety | No |
| Optic Ready | Yes |
| Barrel Length | 16 inches |
| Manual Safety | Yes |
| Overall Length | 33.5 inches |
| Trigger Safety | No |
| Caliber / Gauge | 5.56 NATO, .223 Remington |
| Threaded Barrel | Yes |
| Magazines Included | 1 |
| Ambidextrous Safety | Yes |
| Condition | New |
SIG Sauer M400 SDI X-Series 5.56 NATO Black Rifle
Firearms ship to the FFL dealer you name at checkout. Price and stock are re-checked live when you order.
The SIG Sauer M400 SDI X-Series is a performance-oriented semi-automatic rifle chambered for 5.56 NATO and .223 Remington. Its 16-inch chrome moly barrel pairs with a low-profile gas block and mid-length gas system for balanced handling and dependable cycling. A free-floating M-LOK handguard supports accessory placement without contacting the barrel, while the SIG Flatblade Match Trigger provides a refined trigger pull. The rifle also features an ambidextrous bolt catch and release, an ambidextrous manual safety, a Magpul SL stock, and a hybrid compensator and flash hider.
Key features
- 16-inch chrome moly barrel chambered for 5.56 NATO and .223 Remington
- Free-floating M-LOK handguard provides flexible accessory mounting
- Mid-length gas system supports smooth, balanced operation
- SIG Flatblade Match Trigger offers a crisp, refined trigger pull
- Ambidextrous bolt catch and release improve controls for left- and right-handed users
- Magpul SL stock provides adjustable length of pull for comfortable handling
The SIG Sauer M400 SDI X-Series combines practical controls, a free-floating M-LOK setup, and a match-style trigger in a ready-to-configure rifle platform.
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