Product Description

Maximize the full stopping power, devastating energy transfer, and heavy big-bore accuracy of the 450 Bushmaster "Thumper" cartridge with the complete PRO2A 16" 450 Bushmaster Carbine-Length Non-Reciprocating (NR) Side Charging AR-15 Upper Kit. This master build package provides a meticulously headspaced 16-inch heavy-duty barrel assembly paired with a reliable carbine gas track system and a Gibbz Arms G4 billet side-charging receiver housing. Engineered as an all-in-one component solution, this package comes fully populated with a specialized side-charging M16 profile bolt carrier group, an integrated non-reciprocating charging handle assembly, a complete mil-spec lower parts kit, and a full carbine stock assembly—supplying every essential internal element required to finalize your stripped lower receiver build.

Key Features

• All-Inclusive Master Build Kit: Bundles the complete barreled upper receiver with a premium side-charging bolt carrier group, non-reciprocating charging mechanics, full lower parts kit, and rear receiver stock assembly hardware.
• Non-Reciprocating Left-Side Charger: The patent-pending Gibbz Arms G4 side-charging handle remains stationary during cycling, completely preventing standard rear charging handle interference under heavy hunting scopes or large optics.
• Optimized Big-Bore Velocity: 16-inch structural barrel layout maximizes velocity metrics for devastating kinetic deployment while meeting straight-wall hunting mandates where applicable.
• Precision 1:24 Twist Profile: The tailored 1:24 right-hand twist rate guarantees highly stable rotational flight and enhanced group accuracy for standard commercial heavy-grain 450 Bushmaster loads.
• QPQ Melonite Extreme Armor: Barrel bore, chamber, and exterior are fully liquid nitrocarburized to exceed mil-spec chrome lining in surface hardness, heat dissipation, and corrosion resistance under harsh field handling.
• Slim Profile M-LOK Workspace: Features a continuous top Picatinny rail interface seamlessly blended into a 15-inch free-floating M-LOK handguard for rigid optics and accessory mounting stability.

Technical Specifications

Why Choose This Product?

The PRO2A 16" 450 Bushmaster Carbine Length Non-Reciprocating Side Charging Kit removes the intense frustration of sourcing mismatched large-bore components across separate vendors by providing a perfectly headspaced and balanced ecosystem out of the box. Large-bore straight-walled cartridges place massive mechanical demands on extraction timing and cycling paths. This system handles those pressures smoothly, pairing a single large polished M4 feed ramp layout with a matching specialized side-charging M16 nitride bolt group. Standard rear charging handles complicate manipulation when utilizing oversized hunting glass or thermal optics. By integrating the premium Gibbz Arms G4 side-charging framework, you get clean, unobstructed lever access from a standard firing position. Completed with a full frame parts kit and optimized buffer assembly to actively mitigate thumper recoil lines, it offers a robust, highly reliable big-bore solution backed by a comprehensive Lifetime Structural Warranty.