7.5 inch 4150 Chrome Moly Vanadium barrel in 5.56 NATO with 1:7 twist rate, contour profile, manganese phosphate finish, pistol length gas system, micro low profile steel gas block, 7075-T6 aluminum upper receiver with M4 feed ramps and anodized finish, 7 inch freefloat M-LOK handguard, and GI birdcage flash hider. This pistol upper build kit delivers ultra-compact AR-15 performance in a streamlined package.
The 7.5 inch barrel length creates an ultra-compact package with significantly reduced overall length compared to standard carbine configurations. The 1:7 twist rate stabilizes heavier 5.56 NATO bullets in the 62 to 77 grain range, though velocities will be substantially reduced compared to longer barrels. The contour profile tapers from chamber to muzzle, balancing weight distribution while maintaining structural integrity. The manganese phosphate finish protects against corrosion and provides a durable non-reflective surface. The pistol length gas system uses the shortest standard gas tube length, positioning the gas port closer to the chamber to ensure adequate gas pressure for reliable cycling with the limited barrel length. The micro low profile steel gas block is constructed from steel rather than aluminum, providing increased durability and maintaining gas seal integrity over extended use. The .750 gas block journal provides compatibility with adjustable gas blocks if you want to fine tune gas flow for suppressed use. Expect significant muzzle flash and concussion with this barrel length, particularly with standard ammunition.
The 7 inch freefloat M-LOK handguard extends nearly to the muzzle device on the 7.5 inch barrel, maximizing accessory mounting space while maintaining the compact profile. The M-LOK slots on the sides and bottom allow direct attachment of lights, grips, and other accessories using M-LOK compatible mounts. The freefloat design means the handguard does not contact the barrel, eliminating pressure points that can shift point of impact as the barrel heats. The 7075-T6 aluminum upper receiver features M4 feed ramps machined into the barrel extension interface, improving feeding reliability with a wide range of bullet profiles and magazine types. The anodized finish provides corrosion resistance and matches the handguard for a cohesive appearance.
Follow safe handling and manufacturer instructions. Ensure compliance with all applicable laws. BCG and charging handle are not included.
Caliber: 5.56x45mm NATO
Barrel: Bear Creek Arsenal "Irithyll" AR-15 AR Pistol Barrel 7.5" Contour Barrel 1-7 Twist 5.56 NATO Manganese Phosphate Finish
Barrel Length: 7.5 inches
Barrel Material: 4150 Chrome Moly Vanadium
Barrel Finish: Manganese Phosphate
Barrel Profile: Contour
Barrel Twist Rate: 1:7
Barrel Thread Pitch: 1/2x28
Barrel Gas System Length: Pistol
Gas Block: Micro Low-Profile Gas Block, .750 O.D Barrel Steel
Gas Block Size: 0.750 inches
Handguard Style: Free Float M-Lok
Handguard Color: Black
Upper Receiver: AR-15 Upper Receiver, M4 Feed ramps, 7075 T6 Aluminum, Anodized
Upper Receiver Material: 7075-T6 Aluminum
Upper Receiver Finish: Anodized
Muzzle Device: AR-15 1/2x28 TPI GI Birdcage Flash Hider 5.56 .223 A2
Muzzle Device Finish: Manganese Phosphate
Muzzle Thread Pitch: 1/2x28
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