Out of stock
SKU: 182596
UPC: 814034025676
MPN: FP105556M410RPRBMPSB
The Radical Firearms FP105556M410RPRBMPSB 5.56x45mm NATO upper receiver delivers a compact, purpose-built AR-15 platform optimized for close-quarters tactical operations and precision training. Featuring a 10.50-inch barrel in 5.56 NATO, this upper receiver provides the ballistic efficiency needed for intermediate-range engagements while maintaining the maneuverability essential in confined spaces, vehicle operations, and dynamic entry scenarios.
The 10.50-inch barrel length represents a critical balance in AR-15 design: it retains sufficient velocity to reliably cycle the 5.56x45mm NATO cartridge across standard pressure loads while keeping overall weapon length under 27 inches when paired with a mil-spec collapsible stock. This profile minimizes transit time between shooting positions and improves handling in tight building layouts. Precision machining and tight tolerances ensure consistent accuracy for duty and training applications, with the 5.56 NATO chamber accommodating both military-specification ammunition and commercial loadings.
This upper receiver suits operators, law enforcement tactical teams, and serious rifle builders seeking a short-barrel 5.56 platform without the regulatory complexity of NFA registration. The compact footprint and ballistic characteristics make it effective for home defense, vehicle-based patrol, and indoor range training. Radical Firearms upper receivers are manufactured to mil-spec dimensions and integrate seamlessly with standard AR-15 lower receivers and components, simplifying parts sourcing and maintenance logistics.
The 7.25-pound weight (unloaded, assembled) positions this upper in the mid-range for 5.56 short-barrel AR platforms, balancing suppressive fire capability with shot-to-shot controllability during rapid engagement. The 5.56x45mm NATO caliber remains the standard intermediate cartridge across military and law enforcement agencies worldwide, ensuring ammunition commonality and proven performance data across diverse operational contexts.
WARNING ⚠️ You must be 18 or older to purchase shotgun or rifle ammunition and 21 or older to purchase handgun ammunition and firearms. Please reference our requirements for ammunition orders to "restricted" states HERE. Always make sure you use the correct ammunition for your firearms. Ammo cannot be shipped to a PO Box. Please reference state & local laws before making a firearm or ammunition purchase.
