Details
White Label Grimace .300 Blackout Pistol Upper
The. White. Label. Grimace .300 Blackout pistol upper delivers a compact, suppressor-ready platform built on proven AR-15 architecture. This complete upper features a 7.5-inch 4150 CrMoV barrel with a 1:8 twist rate, 7075-T6 aluminum receiver, and a 7-inch M-LOK handguard. The pistol length gas tube and low-profile gas block are optimized for shorter barrel dynamics, while the 5/8x24 threaded muzzle includes a nitrided flash/sound forwarder and crush washer for immediate compatibility with suppressor-ready setups.
Key Features
- 7.5-inch 4150 CrMoV barrel, phosphate finish, 1:8 twist for .300 Blackout subsonic and supersonic ammunition
- 7075-T6 aluminum upper receiver with anodized finish and M4 feed ramps
- Pistol length gas tube and low-profile 0.750 gas block for compact cycling
- 7-inch M-LOK handguard in 6061-T6 aluminum for accessory mounting
- 5/8x24 nitrided flash/sound forwarder and crush washer included
- Suppressor-ready threaded muzzle for sound reduction compatibility
Perfect For
- Suppressed .300 Blackout pistol builds on compact AR-15 lower receivers
- Subsonic ammunition shooters seeking reliable, quiet performance
- Builders prioritizing short overall length without sacrificing barrel quality
- Tactical pistol configurations with accessory rail flexibility
Suppressor-Ready Design
This upper is built specifically for suppressor mounting. The 5/8x24 thread pitch is the industry standard for .300 Blackout suppressors, and the included flash/sound forwarder provides immediate compatibility. The pistol length gas system is engineered to cycle reliably when suppressed, reducing backpressure concerns common to shorter barrels. The low-profile gas block keeps the sight line clear while maintaining consistent bolt carrier cycling.
Compact Barrel and Gas System
The 7.5-inch barrel length paired with pistol length gas tubing creates a balance between velocity and portability. The 4150 CrMoV material and phosphate finish provide durability for both subsonic and supersonic .300 Blackout loads. The 1:8 twist rate stabilizes the full range of .300 Blackout projectiles, from lightweight 110-grain rounds to heavier 220-grain subsonic ammunition.
M-LOK Accessory Platform
The 7-inch M-LOK handguard offers mounting flexibility without excessive length. The 6061-T6 aluminum construction keeps weight minimal while providing a solid platform for lights, lasers, or vertical grips. The handguard geometry accommodates pistol-length configurations while maintaining ergonomic control.
FAQ
What ammunition does the 1:8 twist rate support?
The 1:8 twist is optimized for .300 Blackout across the full velocity spectrum. It stabilizes 110-grain supersonic rounds reliably and handles heavier 220-grain subsonic loads without overstabilization concerns.
Is this upper compatible with standard AR-15 lower receivers?
Yes. This is an AR-15 platform upper and accepts any standard AR-15 lower receiver with mil-spec trigger pin spacing.
What's included with this upper?
The upper assembly includes the barrel, upper receiver, handguard, gas tube, gas block, and a nitrided flash/sound forwarder with crush washer. BCG and charging handle are not included.
Can I use this without a suppressor?
Yes. The muzzle device functions as a flash/sound forwarder even without a suppressor attached. However, the upper is optimized for suppressed fire and performs best in that configuration.
What suppressor thread pitch do I need?
The barrel is threaded 5/8x24, which is standard for .300 Blackout suppressors. Verify your suppressor matches this specification before mounting.
Follow safe handling and manufacturer instructions. Ensure compliance with all applicable federal, state, and local laws. BCG and charging handle are not included. Verify compatibility before use. Ensure secure mounting before operation. Use only in accordance with applicable laws.
