Sig Sauer
MCX-SPEAR LT 9 AR CONVERSION KIT 300BLK- FDE
Item # SIG WUAMCXA-300B-9B-LT-FDE MSRP $1,999.00PRODUCT DETAILS
TECH SPECS:
Convert your existing rifle lower into the next generation of MCX performance with the SIG MCX-SPEAR LT Conversion Kit, finished in durable Flat Dark Earth (FDE). This complete kit is designed to transform any MIL-SPEC AR-15/M4 lower into a compact, modern MCX-SPEAR LT platform while delivering the accuracy, reliability, and modularity SIG is known for.
The kit includes a factory-built complete 9" 300 Blackout upper assembly featuring a removable 3-prong flash hider that is ready to accept SIG’s SLH and SLX suppressor systems. Also included is the receiver extension delete stock adapter, allowing compatibility with vertical 1913-rail mounted folding or static stocks and braces for true MCX-style configuration capability.
Chambered in 300 BLK, this upper is optimized for short-barrel performance and excels with both subsonic and supersonic ammunition. Its compact profile makes it ideal for users seeking reduced overall length without sacrificing ballistic performance.
Designed for broad platform compatibility, this conversion kit works with SIG MCX, M400, 516, and any MIL-SPEC AR-15/M4 lower, providing a seamless upgrade path to the SPEAR LT system without purchasing a complete firearm.
Key Features
-
Converts MIL-SPEC lowers into MCX-SPEAR LT configuration
-
Complete 9" 300 BLK upper assembly in Flat Dark Earth (FDE)
-
Removable 3-prong flash hider, suppressor-ready
-
Accepts SLH and SLX SIG suppressor systems
-
Includes receiver extension delete adapter
-
Compatible with 1913-interface stocks and braces
-
Thread pitch: 5/8 x 24
-
Compatible with MCX, M400, 516, and MIL-SPEC AR-15/M4 lowers
NFA Disclaimer / Legal Notice
This upper receiver has a barrel length under 16 inches. When assembled into a complete rifle, it is considered a Short-Barreled Rifle (SBR) under federal law and requires registration and a tax stamp with the Bureau of Alcohol, Tobacco, Firearms and Explosives (ATF/BATFE).
Additional state and local restrictions may apply.
The buyer is solely responsible for compliance with all applicable laws.
| MCX-SPEAR LT Conversion Kit 9" 300 BLK FDE (WUAMCXA-300B-9B-LT-FDE) | |
|---|---|
| Caliber | 300 Blackout (300 BLK) |
| Barrel Length | 9 inches |
| Upper Assembly | Complete 9" 300 BLK Upper |
| Thread Pitch | 5/8 x 24 |
| Flash Hider | Removable 3-Prong – SLH/SLX Suppressor Ready |
| Stock / Brace Interface | Receiver Extension Delete Adapter – Vertical 1913 Rail |
| Compatible Lowers | MCX, M400, SIG 516, MIL-SPEC AR-15/M4 |
| Platform Type | Conversion Kit – Upper Receiver Assembly |
| NFA Status | Sub-16" Barrel – SBR Rules Apply When Assembled |
Questions 0
Ask a QuestionProven Arms & Outfitters A bolt-action rifle requires the shooter to manually operate a bolt to load a round, eject the spent casing, and chamber the next round. In contrast, a semi-automatic rifle is designed to automatically eject the spent casing and chamber a new round with each pull of the trigger. Semi-automatic rifles offer faster follow-up shots, while bolt-action rifles are typically more accurate due to their design.
SORT BY MOST RECENT
No Customer Review on this product
PRODUCT DETAILS
TECH SPECS:
Convert your existing rifle lower into the next generation of MCX performance with the SIG MCX-SPEAR LT Conversion Kit, finished in durable Flat Dark Earth (FDE). This complete kit is designed to transform any MIL-SPEC AR-15/M4 lower into a compact, modern MCX-SPEAR LT platform while delivering the accuracy, reliability, and modularity SIG is known for.
The kit includes a factory-built complete 9" 300 Blackout upper assembly featuring a removable 3-prong flash hider that is ready to accept SIG’s SLH and SLX suppressor systems. Also included is the receiver extension delete stock adapter, allowing compatibility with vertical 1913-rail mounted folding or static stocks and braces for true MCX-style configuration capability.
Chambered in 300 BLK, this upper is optimized for short-barrel performance and excels with both subsonic and supersonic ammunition. Its compact profile makes it ideal for users seeking reduced overall length without sacrificing ballistic performance.
Designed for broad platform compatibility, this conversion kit works with SIG MCX, M400, 516, and any MIL-SPEC AR-15/M4 lower, providing a seamless upgrade path to the SPEAR LT system without purchasing a complete firearm.
Key Features
-
Converts MIL-SPEC lowers into MCX-SPEAR LT configuration
-
Complete 9" 300 BLK upper assembly in Flat Dark Earth (FDE)
-
Removable 3-prong flash hider, suppressor-ready
-
Accepts SLH and SLX SIG suppressor systems
-
Includes receiver extension delete adapter
-
Compatible with 1913-interface stocks and braces
-
Thread pitch: 5/8 x 24
-
Compatible with MCX, M400, 516, and MIL-SPEC AR-15/M4 lowers
NFA Disclaimer / Legal Notice
This upper receiver has a barrel length under 16 inches. When assembled into a complete rifle, it is considered a Short-Barreled Rifle (SBR) under federal law and requires registration and a tax stamp with the Bureau of Alcohol, Tobacco, Firearms and Explosives (ATF/BATFE).
Additional state and local restrictions may apply.
The buyer is solely responsible for compliance with all applicable laws.
| MCX-SPEAR LT Conversion Kit 9" 300 BLK FDE (WUAMCXA-300B-9B-LT-FDE) | |
|---|---|
| Caliber | 300 Blackout (300 BLK) |
| Barrel Length | 9 inches |
| Upper Assembly | Complete 9" 300 BLK Upper |
| Thread Pitch | 5/8 x 24 |
| Flash Hider | Removable 3-Prong – SLH/SLX Suppressor Ready |
| Stock / Brace Interface | Receiver Extension Delete Adapter – Vertical 1913 Rail |
| Compatible Lowers | MCX, M400, SIG 516, MIL-SPEC AR-15/M4 |
| Platform Type | Conversion Kit – Upper Receiver Assembly |
| NFA Status | Sub-16" Barrel – SBR Rules Apply When Assembled |
SORT BY MOST RECENT
No Customer Review on this product
Questions 0
Ask a QuestionProven Arms & Outfitters A bolt-action rifle requires the shooter to manually operate a bolt to load a round, eject the spent casing, and chamber the next round. In contrast, a semi-automatic rifle is designed to automatically eject the spent casing and chamber a new round with each pull of the trigger. Semi-automatic rifles offer faster follow-up shots, while bolt-action rifles are typically more accurate due to their design.
