Lower receivers are the legal and functional heart of any AR build—from AR‑15 and AR‑10 rifles to AR‑9 platforms. At Arm or Ally, we offer a comprehensive selection of stripped lowers, complete lowers, and matched receiver sets, all sourced from trusted manufacturers to give builders the quality and compatibility they demand. We carry Aero Precision stripped and complete lowers—machined from 7075‑T6 aluminum to Mil‑Spec tolerances. Options include anodized finishes, Cerakote coatings, integrated trigger guards, threaded bolt catch pins, and compatibility across AR‑15, AR‑10 (.308), and AR‑9 platforms. Also available are Bravo Company complete lowers featuring SOPMOD-style stocks, Gunfighter configurations, and Mil‑Spec assemblies ready to pair with any upper receiver you choose. For AR‑10 or big‑bore rifle builders, Aero Precision’s M5 lower receivers offer full compatibility with DPMS-style upper components. These models feature a flared magwell, rear tensioning screw, and precise machining that supports reliable long-range accuracy and durability. We also carry Aero Precision matched receiver sets that pair an upper and lower receiver together from the factory for improved alignment and aesthetics. These sets often include enhanced features like threaded takedown pin detents, upper tension screws, and clean Cerakote finishes. Looking to start with a blank canvas? Our stripped lower receivers are ideal for custom builds. Aero’s Gen 2 lowers include thoughtful features like an integrated trigger guard, beveled magwell, and compatibility with most Mil‑Spec parts kits. Many of these models are offered in black anodized, FDE, OD Green, Kodiak Brown, or specialty Cerakote finishes to match your style and build requirements. We also carry components from Breek Arms, including accessories that complement lower receivers like castle nuts, end plates, and buffer retention kits—ideal for builders who want quality parts at competitive prices. For lower parts kits and buffer assemblies, we stock trusted brands like Magpul and Ballistic Advantage, making it easy to complete your build with quality internals and ergonomic upgrades. Need a complete lower? Aero Precision and Bravo Company both offer fully assembled lowers with Magpul MOE grips and either SBA3 pistol braces or adjustable stocks. These are ideal for those looking to skip assembly and jump straight into pairing a complete upper. For AR‑9 builds, Aero Precision EPC-9 lower receivers offer dedicated functionality for pistol caliber carbines. These models support Glock®-pattern magazines and integrate last-round bolt hold open and flared magwells for smoother reloads. Every serialized lower receiver purchase through Arm or Ally follows a streamlined FFL transfer process. During checkout, you can select or submit your preferred FFL dealer. Once the license is received and verified, we ship directly to your dealer for easy local pickup and compliance. Our site allows filtering by platform (AR‑15, AR‑10, AR‑9), receiver type (stripped, complete, matched set), finish, and price range—helping you find the perfect lower receiver fast. We also clearly mark blemished options for customers looking to save on functional, cosmetic-second components. With fast shipping, competitive pricing, and support from a team that understands what builders need, Arm or Ally is the trusted destination for high-performance lower receivers. Whether you're planning a match-grade setup, lightweight build, or clone rifle, we have the quality receivers and parts to help you build with confidence.