Description
The Sig MCX Virtus SBR 300 Blackout, 9″, Flat Dark Earth, Tele Fold Stock, Alum M-LOK Handguard, 1x30rd Mag is a factory-built, short-barreled rifle designed for suppressed use and close-quarters dominance. Chambered in 300 BLK, its 9-inch barrel optimizes subsonic ammunition, while the folding stock and compact profile make it a formidable tool for home defense and tactical applications where maneuverability is non-negotiable.
Key Features
- Optimized 300 BLK Platform: The 9-inch barrel length is the sweet spot for the 300 Blackout cartridge, ensuring full powder burn and maximum performance with both supersonic and subsonic loads, especially when paired with a suppressor.
- Folding & Telescoping Stock: The SIG telescoping and folding stock collapses for ultra-compact storage or transport and provides a solid, adjustable cheek weld when deployed. It folds independently of the charging handle, allowing the weapon to be fired while folded in an emergency.
- Virtus Aluminum M-LOK Handguard: Provides a rigid, lightweight mounting platform for lights, lasers, and vertical grips. The full-length top Picatinny rail maintains optic and sight compatibility with standard AR patterns.
- Short-Stroke Piston System: Unlike direct-impingement ARs, the MCX’s piston system runs cleaner, cooler, and more reliably. It drastically reduces fouling in the receiver and allows for easy adjustment for suppressed firing.
- Out-of-the-Box SBR: This is a factory SBR, not a pistol brace configuration. It’s drop-in ready for the NFA process, requiring only the standard FFL/SOT transfer for approved individuals.
Specifications & Details
| Caliber | 300 AAC Blackout |
| Barrel Length | 9 inches |
| Overall Length (Stock Extended) | Approx. 28.5-31.75 in (adjustable) |
| Weight (Unloaded) | Approx. 6.75 lbs |
| Handguard | Aluminum M-LOK |
| Stock | SIG Telescoping & Folding |
| Magazine | 1x 30-round SIG SR-25/PMAG compatible |
When it comes to home defense, a weapon that’s easy to maneuver in hallways, doesn’t over-penetrate with the right ammunition, and pairs seamlessly with a suppressor is a serious advantage. The MCX Virtus SBR in 300 BLK is built for that exact scenario. Its folded length of under 20 inches means it can be stored in remarkably small spaces, yet it deploys instantly to a stable firing platform. The adjustable gas block lets you tune the system to run flawlessly with a can—think about the auditory and flash advantages in a low-light, high-stress situation. At a price of $1861.19, it represents a significant but purpose-driven investment in a professional-grade system.
Who This Rifle Is For
This SBR is for the serious end-user who understands the NFA process and demands a compact, suppressor-ready weapon system from a proven manufacturer. It’s ideal for tactical professionals, seasoned home defenders who prioritize a minimized signature, and shooters who want a modern piston-driven alternative to the traditional AR-15 SBR. It’s also a perfect companion for those who already run a SIG pistol like the P320 or P226 and want platform familiarity. This model is available at firearms-missouri.com for Missouri residents and nationwide to qualified purchasers through their local FFL.
Pros & Cons
Pros: Superior piston-driven reliability and clean operation; ideal barrel length for 300 BLK ballistic performance; factory SBR configuration saves time and hassle; folding stock enables extreme compactness; fully ambidextrous controls; M-LOK handguard offers modern attachment options.
Cons: Requires NFA tax stamp and paperwork, adding cost and wait time; proprietary bolt carrier and recoil system means some parts aren’t interchangeable with standard AR-15s; the premium price point places it above entry-level options. That said, you’re paying for a complete, integrated system, not just a collection of parts.
Frequently Asked Questions
Q: Is this a complete rifle or just an upper receiver?
A: This is a complete, factory-built Short-Barreled Rifle (SBR). It ships as a full firearm and requires an FFL/SOT transfer for the NFA item. You cannot purchase it as just an upper receiver for an existing lower without the proper tax stamp for that configuration.
Q: What magazines does it use?
A: The MCX Virtus in 300 Blackout uses magazines compatible with the SR-25/DPMS .308 pattern. This includes Magpul PMAG 300 BLK specific magazines, which are highly recommended for reliable feeding, as well as SIG and other branded 300 BLK SR-25 magazines. It comes with one 30-round magazine.
Q: Can I attach my own suppressor?
A: Absolutely. The barrel features a standard 5/8×24 thread pitch, which is the common thread for .30 caliber suppressors. You can mount popular models from SilencerCo, Dead Air, SureFire, and others. Remember to use the adjustable gas block to tune the system when running suppressed.
Ready to process the NFA paperwork for one of the most capable compact rifle systems available? Configure your ideal setup and begin the process through our network.
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