AR-15 Upper & Lower Receivers
AR receivers are the structural foundation of a rifle build. The upper receiver houses the barrel, bolt carrier group, and handguard interface; the lower receiver holds the fire-control group, magazine well, and buffer system. Getting fitment right between forged or billet receivers, complete uppers, and supporting parts is what turns a parts list into a rifle that runs—caliber, gas length, and rail choice all flow from those two halves.
PHLX Tactical’s AR Receivers category focuses on complete AR upper assemblies plus pathways into upper components and lower components. Use it to start a new AR-15 or AR-10-style project, replace a worn upper, or gather the pins, springs, and controls that finish a lower. Product pages call out barrel length, handguard style, and included BCG or charging handle where applicable. Cross-link into handguards, BCGs, and barrels from the Retail Shop when you are assembling a full bill of materials.
If you need receivers or related firearm components machined to print for private-label or OEM programs, see OEM firearm parts—that channel is quote-driven and distinct from ready-to-ship catalog items.
What you’ll find in this category
- Complete AR-15 (and related platform) upper receivers in common barrel lengths and rail setups
- Upper components for barrels, charging handles, and build-critical upper hardware
- Lower components including LPKs, pins, springs, detents, and fire-control-related parts
- Options spanning range, hunting, and duty-oriented configurations from established brands
- Clear paths to related categories—handguards, BCG & triggers, and barrels—for a full build
Frequently asked questions
What is the difference between an upper and a lower receiver?
The upper receiver assembly typically includes the upper forging or billet, barrel, gas system, handguard, BCG, and charging handle. The lower receiver holds the trigger group, pistol grip, stock or brace interface, and magazine well. Most builders mate a complete or stripped upper to a compatible lower; always verify caliber, platform (e.g., AR-15 vs. AR-10 patterns), and local purchasing rules before you buy.
Should I buy a complete upper or build from parts?
A complete upper is the faster path when you want a matched barrel, rail, and (often) BCG and charging handle already assembled. Building from stripped receivers and components offers more control over each part choice and is common for custom or specialty setups. Either route works—choose based on time, tools, and how specific your parts list needs to be.
Do you offer OEM or custom receiver machining?
Catalog receivers and related retail parts are listed here and across the Retail Shop. For build-to-print receiver or firearm-component programs, contact us through OEM firearm parts with prints and requirements; OEM work is quoted separately from online inventory.
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