Davidson Defense Assegai 18-inch Mid-Gas 1:24 .450 Bushmaster AR-15 M-Lok Rifle Upper Build Kit

Assegai 18-Inch Mid-Gas 1:24 .450 Bushmaster AR-15 M-LOK Rifle Upper Build Kit

The Assegai Upper Build Kit is built around an 18-inch .450 Bushmaster "Sepal" HBAR barrel with a mid-length gas system, a "Panhead" billet upper receiver with an enlarged .458-style ejection port, and a 15-inch free-float M-LOK handguard. BCG and charging handle are not included.

Key Features

• 18-inch "Sepal" .450 Bushmaster HBAR barrel, 4150 CMV steel, 1:24 twist, Phosphate finish
• Mid-length gas system
• "Panhead" billet upper receiver with enlarged .458-style ejection port
• 15-inch free-float M-LOK handguard, black
• KAK Industry .458 compensator (COMP-5/8-32-458) on 5/8x32 threads with 5/8-inch black crush washer
• BCG and charging handle are not included.

Barrel and Gas System

The 18-inch "Sepal" barrel is machined from 4150 chrome moly vanadium steel in an HBAR heavy profile with a Phosphate finish and a 1:24 twist rate suited to .450 Bushmaster. It runs a mid-length gas system through a stainless steel gas tube and a micro low-profile steel gas block with a .750-inch diameter, matched to the barrel's .750-inch gas journal. At the muzzle, 5/8x32 threads carry the included KAK Industry .458 compensator, secured with the supplied 5/8-inch black crush washer.

Upper Receiver and Handguard

The upper receiver is a billet "Panhead" unit with an enlarged .458-style ejection port sized for the larger case head of .450 Bushmaster, built in a NOFA (no forward assist) configuration, and it includes the ejection port door, rod, and spring. It's paired with a 15-inch free-float M-LOK handguard finished in black.

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