Choosing AR-platform parts starts with confirming the firearm platform, caliber, component dimensions, mounting interface, manufacturer specifications, and compatibility with the existing upper or lower receiver assembly.

Common AR-Platform Parts

• Upper Receiver Components: Upper receivers, barrels, bolt carrier groups, charging handles, gas blocks, gas tubes, muzzle components, handguards, and related parts used in the upper assembly.
• Lower Receiver Components: Lower parts kits, triggers, selectors, takedown pins, magazine releases, bolt catches, buffer components, grips, stocks, and other lower-receiver hardware.
• Barrels and Bolt Carrier Groups: Available in multiple calibers, barrel lengths, profiles, gas-system lengths, bolt configurations, finishes, and specifications for compatible AR-platform firearms.
• Handguards and Rail Systems: Free-float and drop-in configurations may use M-LOK, Picatinny, KeyMod, or other mounting interfaces depending on the firearm and accessory requirements.
• Stocks, Braces and Grips: Available in different sizes, materials, shapes, adjustment systems, and mounting configurations to suit compatible firearms and individual preferences.

AR-15 vs. AR-10 Compatibility

AR-15 and AR-10 style firearms share many design concepts, but components are not universally interchangeable. AR-10 and other large-frame platforms can also vary between manufacturers. Always confirm the exact platform, caliber, receiver pattern, barrel extension, bolt, handguard, buffer system, and other dimensional requirements before selecting replacement or upgrade parts.

Choosing Replacement and Upgrade Parts

When replacing or upgrading components, compare the original firearm specifications with the new part's dimensions, caliber rating, interface, materials, and manufacturer compatibility information. Some components may require proper installation, fitting, torque specifications, headspace verification, or inspection by a qualified gunsmith.