Choosing a lower receiver starts with identifying the firearm platform, receiver pattern, caliber family, component compatibility, material, finish, and whether a stripped or complete lower better fits the intended application.

Common Lower Receiver Types

• Stripped Lower Receivers: Generally provide the receiver itself without the complete fire-control components, buffer system, grip, or stock assembly, allowing compatible components to be selected separately.
• Complete Lower Receivers: Typically include installed lower components and may include a grip, buffer assembly, stock, brace, or other manufacturer-specified equipment depending on the configuration.
• AR-15 Lower Receivers: Designed around compatible AR-15-pattern components and commonly used with a wide variety of upper receivers, parts, and caliber configurations where manufacturer compatibility allows.
• AR-10 / .308 Lower Receivers: Designed for larger-frame AR-type platforms. Unlike many AR-15 components, large-frame receiver patterns are not universally standardized, making manufacturer and component compatibility especially important.

Forged vs. Billet Lower Receivers

Forged lowers are manufactured from forged aluminum that is machined to final dimensions and are widely used across AR-pattern platforms. Billet lowers are machined from solid material and may incorporate distinctive contours, integrated features, ambidextrous controls, or other manufacturer-specific design elements.

Stripped vs. Complete Lower Receivers

A stripped lower provides more flexibility when selecting individual compatible parts, while a complete lower can reduce the number of separate components needed. Before purchasing, confirm compatibility between the lower receiver, upper receiver, fire-control components, buffer system, stock or brace configuration, magazines, and intended cartridge.

Receiver Compatibility

AR-15-pattern components have broad compatibility, but individual manufacturer specifications still matter. AR-10 and .308-pattern platforms can vary more substantially in receiver geometry, takedown-pin locations, upper and lower fit, buffer systems, and other components. Always confirm compatibility before combining parts from different manufacturers.

Lower Receiver Transfers

Under federal law, a firearm frame or receiver is itself included within the definition of a firearm. Serialized lower receivers therefore require applicable firearm transfer procedures when sold or transferred through a dealer. :contentReference[oaicite:0]{index=0}

For additional information, review our guide to buying firearms online or see our FFL transfer information .