ATI Ar-15 Multi Rifle receiver/AR-15 platform component

The ATI AR-15 Multi Caliber Receiver in black is a stripped lower receiver built from 7075-T6 aircraft-grade billet aluminum, engineered as the foundation for custom AR-15 builds across multiple caliber platforms. This precision-machined component is the licensed firearm component of your build—the part that legally defines the weapon—making receiver quality and dimensional accuracy critical to overall reliability and longevity.

Machined from 7075-T6 aluminum, this receiver combines strength with lightweight construction. The mil-spec compatibility ensures the lower interfaces correctly with standard AR-15 upper assemblies, buffer tubes, and fire control groups across the market. Multi-caliber compatibility means a single lower receiver platform accepts uppers chambered in 5.56 NATO, .223 Remington, .300 Blackout, 7.62x39, and other common intermediate cartridges—a significant advantage for operators and enthusiasts managing multiple configurations without duplicating lower receiver investment.

This stripped lower is ideal for custom builders, patrol units managing platform consistency, and shooters who want precision control over component selection. Stripped lowers require the addition of fire control parts (trigger group, safety, bolt catch, magazine release) to function—a process suited to experienced builders or gunsmiths. The black finish provides corrosion resistance suitable for field environments. Compliance with federal firearm regulations applies; this is a regulated firearm component and is subject to background check requirements at the point of sale.