Details
Breach 9mm Pistol Upper
The Breach 9mm Pistol Upper combines a 4.5-inch 4150 CrMoV barrel with a 7075-T6 aluminum receiver for a compact, reliable AR-9 platform. The nitride-finished barrel resists corrosion while the free-float M-LOK handguard maintains accuracy and allows full customization of your setup. This upper is built for shooters who want precision in a smaller package without sacrificing durability or control.
Key Features
- 4.5-inch nitride-treated 4150 CrMoV barrel with 1:10 twist rate
- 7075-T6 aluminum receiver with anodized finish
- 4-inch M-LOK free-float handguard for accessory mounting
- 9mm flash hider A2 birdcage muzzle device with crush washer
- Forward assist assembly and ejection port door included
- M4 feed ramp for reliable chambering
Compact AR-9 Design
This upper delivers the handling advantages of a shorter barrel while maintaining the reliability of the AR-9 platform. The 4.5-inch barrel length balances velocity and maneuverability, making it suitable for both bench shooting and dynamic environments. The nitride finish on the barrel provides superior corrosion resistance compared to standard parkerizing, extending the life of your upper under regular use.
Free-Float Handguard System
The M-LOK free-float handguard eliminates contact between the barrel and rail system, allowing the barrel to vibrate naturally without interference. This design improves consistency across different shooting conditions and ammunition types. The 4-inch length provides mounting flexibility while keeping the overall package compact. M-LOK slots run the full length, giving you multiple options for light mounts, rail segments, or other accessories.
Precision Barrel and Receiver Pairing
The 7075-T6 aluminum receiver paired with the 4150 CrMoV barrel creates a durable foundation for your build. The receiver's anodized finish protects against wear and corrosion during handling and use. The barrel's medium profile balances weight and heat retention, important for sustained fire without excessive barrel rise. The 1:10 twist rate stabilizes 9mm projectiles across a wide range of bullet weights.
Included Components and Compatibility
This upper includes a forward assist assembly, ejection port door with rod and spring, 9mm flash hider with crush washer, and all hardware needed for assembly to a compatible lower receiver. BCG and charging handle are not included. The 1/2x36 thread pitch on the barrel accepts standard 9mm suppressors and muzzle devices. The M4 feed ramp ensures reliable feeding when paired with 9mm lower parts kits designed for this platform.
Follow safe handling and manufacturer instructions. Ensure compliance with all applicable federal, state, and local laws. BCG and charging handle are not included.
