Brownells BRN XB2 MT Pro SPR 300 BLK Rifle w/ Stabilizing Brace

The Brownells BRN XB2 MT Pro SPR delivers precision shooting performance in 300 Blackout with a compact, maneuverable platform. This rifle combines proven AR-15 ergonomics with enhanced stability features for both subsonic and supersonic ammunition applications.

What Makes This Different

Built on a forged 7075-T6 aluminum receiver set, this rifle features a specialized barrel profile optimized for 300 Blackout ballistics. The stabilizing brace configuration provides enhanced control while maintaining compact dimensions. Unlike standard carbine setups, the MT Pro barrel delivers consistent accuracy across the full range of 300 BLK ammunition weights from 110-grain supersonic to 220-grain subsonic loads.

Key Features

• 300 Blackout chambering with 1:7 twist rate for optimal bullet stabilization
• Forged aluminum upper and lower receivers with Type III hard coat anodizing
• Stabilizing brace system for improved shooting control and portability
• M-LOK compatible handguard with multiple attachment points
• Mil-spec trigger group with standard AR-15 fire control components
• Threaded muzzle with A2-style flash hider included
• Standard AR-15 magazine compatibility for easy ammunition feeding

The rifle excels in close-quarters applications where maneuverability matters most. Law enforcement and civilian users benefit from the 300 Blackout's effectiveness at shorter ranges while maintaining compatibility with standard AR-15 accessories. The platform handles both suppressed and unsuppressed shooting scenarios effectively, with the subsonic capability providing tactical advantages in noise-sensitive environments.

Technical Specs

• Caliber: 300 AAC Blackout (.300 BLK)
• Barrel length: Approximately 10.5-12.5 inches (varies by configuration)
• Overall length: 26-30 inches (depending on brace position)
• Weight: 6.5-7.5 pounds unloaded
• Twist rate: 1:7 inches for heavy bullet stabilization
• Gas system: Pistol-length with adjustable gas block
• Handguard: M-LOK aluminum with anti-rotation design
• Finish: Type III hard coat anodized black
• Magazine capacity: Accepts standard AR-15 magazines
• Manufactured in the United States

This configuration addresses the growing demand for compact, versatile rifles that maintain full-power performance. The 300 Blackout chambering provides superior terminal ballistics compared to pistol calibers while keeping the familiar AR-15 manual of arms that shooters already know.