PRO2A 7.5" 450 Bushmaster 1/24 Pistol Length Melonite NR Side Charging M-LOK AR-15 Upper Kit

Product Overview

The PRO2A 7.5" 450 Bushmaster 1/24 Pistol Length Melonite NR Side Charging M-LOK AR-15 Upper Kit brings massive, close-quarters straight-walled big-bore performance into a high-ergonomic master builder configuration. Chambered fully in .450 Bushmaster, this conversion package replaces the traditional mil-spec rear latch layout with a modern Non-Reciprocating (NR) Left-Side Charging Upper Receiver system. Engineered around an optics-ready layout and a premium 7.5-inch Melonite-treated heavy contour profile barrel, this package handles severe short-barrel operating pressures with absolute control. The comprehensive master bundle ships completely assembled and headspaced on the upper receiver, packed together with a dedicated side-charging Nitride bolt carrier group, a full lower hardware internal completion parts group, and an adjustable pistol stabilizing blade setup for immediate operational deployment.

Key Features

Non-Reciprocating Side Charging (NRSC) Handle: Upgrades manipulation ergonomics by keeping the charging handle stationed forward while firing—preventing moving interference with your grip while allowing rapid left-side cycling without lifting your head from the brace.
Complete Master Builder Bundle: Takes the technical guesswork out of big-bore procurement by completely grouping a pre-assembled side-charge upper receiver, pre-headspaced side-charging bolt group, complete internal lower parts kit hardware, and a matching buffer stabilization package.
Modified Big-Bore Upper Receiver: Precision machined with an custom-enlarged ejection port layout designed explicitly to facilitate flawless, high-velocity extraction clearance for massive .450 Bushmaster brass casings.
Advanced QPQ Melonite Protection: Liquid salt-bath nitride surface treatment shields internal rifling and external steel paths against high-thermal wear, intense pressure scores, and moisture corrosion.
Stabilizing Blade Assembly Component: Ships with a high-durability polymer pistol stabilizing blade brace and high-tensile receiver buffer system to balance heavy big-bore recoil impulses and preserve clean point-of-aim tracking.
Slim Free-Float M-LOK System: Free-floated aluminum rail layout isolates barrel harmonic variables to preserve uniform grouping accuracy while adding a continuous top Picatinny rail axis and modular side M-LOK accessory space.

Technical Specifications

Charging System Orientation	Left-Side Non-Reciprocating (NR) Side-Charging Upper Assembly; Forward Handle Remains Stationary While Firing
Upper Receiver Base Architecture	Gibbz Arms G4 Billet Aluminum, Custom-Enlarged Ejection Port for Big-Bore Brass Clearance, Single Large Feed Ramp, Type III Hardcoat Anodized Matte Black Finish
Charging Handle Setup Adjustment	Tension-adjustable forward retention layout; side handle operates smoothly past the factory mechanical detent path
Bolt Carrier Group (BCG)	Full M16 Profile, 9310 Steel Bolt, Slick QPQ Black Nitride Treatment, MPI Tested, Properly Staked Gas Key Layout
Barrel Length & Contour	7.5 Inches; Heavy Contour Profile
Barrel Material Composition	4150 Chrome Moly Vanadium (CMV) Steel
Twist Rate Profile	1:24 Twist (Optimized for heavy straight-wall big-bore loads)
Barrel Coating Finish	QPQ Melonite / Premium Black Nitride Exterior and Interior Lining for Maximum Corrosive Resistance
Gas Operating System	Pistol-Length Gas System with 0.750" Low Profile Gas Block, High-Tensile Stainless Steel Gas Tube Layout
Muzzle Thread & Device	5/8x24 TPI (Thread Pitch Layout); Equipped with Standard Big-Bore Flash Hider
Handguard Rails Profile	7 Inch Slim Profile Free-Float Aluminum Handguard, Integrated Top Picatinny Rail Alignment, Matrixed M-LOK Structural Slots
Lower Receiver Parts Kit (LPK)	Complete Mil-Spec Internal Hardware Small Components (Springs, Detents, Pins), Single-Stage Fire Control Trigger Group Assembly (Trigger, Hammer, Disconnector), and Standard Mil-Spec A2 Pistol Grip
Blade Assembly Setup	Polymer Pistol Stabilizing Blade Brace, Heavy-Duty AR-15 Pistol Buffer Tube, 3oz Carbine Buffer, and High-Tensile Recoil Buffer Spring Group
Manufacturing Origin & Quality	100% Proudly Assembled, Timed, and Quality Checked in the USA with Pro2A Tactical Lifetime Factory Warranty

Why Choose the PRO2A Non-Reciprocating Side-Charging 450 Bushmaster Pistol Kit?

Why Choose the PRO2A Non-Reciprocating Side-Charging 450 Bushmaster Pistol Kit?Harnessing a thumping .450 straight-walled cartridge inside an ultra-short AR platform demands precision engineering from the bolt lugs to the receiver frame. Standard rifle receivers cause catastrophic stovepipe malfunctions and failure-to-extract errors because narrow mil-spec ejection openings cannot clear wide straight-walled brass. Pro2A Tactical eliminates this engineering barrier directly on the manufacturing line—utilizing custom-expanded ejection channel tracks paired with a matching, pre-headspaced side-charging 9310 steel bolt face to guarantee consistent extraction strings. By moving the cycle layout to a left-side ergonomic handle, you can clear chamber actions or load heavy rounds intuitively while keeping your eyes completely downrange, overcoming the awkward clearance issues of large optics and standard charging latches on a compact frame. By aligning an ultra-hard 7.5" Melonite heavy barrel to an integrated lower component setup and matching pistol stabilizing blade brace, this master build kit delivers a cycle-tuned, unified shooting ecosystem designed for absolute short-barrel reliability.