AR-15 Weapons Platform Family

Major AR Family Members

• The AR-15 is the most commercially successful of the AR family. The M-16 is simply a select-fire version of the AR-15, as is the M-4.
• The AR-10 is a 308 rifle based off of Eugene Stoner's earlier design.
• Unrelated except in name, the AR-180 used a stamped receiver and shared no parts with the AR-15 as originally shipped. However, it seems that AR-15 FCG parts could in fact be used in it, just not in a configuration which resembled the original Armalite FCG. It also did not accept STANAG magazines. The AR-180 and AR-180B are usually what cause folks to exclaim that they've seen an AR-15 upper with a side-mounted charging handle.
• The AR-180B (newer rifle) apparently shares more parts with the AR-15, and does accept STANAG magazines.

Generic Description of the AR Platform

The rifle has a lower receiver, which contains the trigger, stock, and grip. A magazine well is also included, but it might not be used, depending on how the rifle is configured. Certain variants of the AR system are designed with a sealed up magazine well, or NO magazine well (single-shot) in order to avoid legal issues with certain states.

The rifle has an upper receiver, which contains the barrel, gas operating system, etc. In most cases, this is a gas-operated semi-automatic. In some cases, such as the 50 BMG upper receiver, the upper receiver uses a bolt.

Upper receiver choices include traditional semi-automatic uppers, single-shot bolt-action uppers, and a plethora of different calibers. There are a number of them listed below; some bargains are referenced on specific pages. People are welcome to add more information for any of these calibers.

For a more general list of AR parts for sale, hit the AR-15 shopping page.

AR-family rifles in 308

• Compatibility Chart

Building an AR-15

• Preparing parts for a build
• AR-15 Buttstocks - fixed and collapsible, choosing the one you want, and installing either one (with pictures)
• Assembling an AR-15 Lower Receiver
  • Different Magazine Release Assemblies
    • Installing a Standard Magazine Release Mechanism
    • Installing a Sporting Conversion Maglock (California, first-generation fixed mag compliance device)
  • Installing the Bolt Catch Assembly
  • Installing the Front Pivot Pin
  • Installing a Collapsible Buttstock on an AR-15
  • Installing a Fixed Buttstock on an AR-15
• Installing a Front Sight Base on a virgin barrel
• Installing a Phase 5 EBR (optional; replaces standard bolt catch)
• Installing an Accu-Wedge (optional)
• Installing a Receiver Rug (optional)
• Iron Sights on the AR-15 platform
• Analysis of a Rock River Arms 9mm

California Compliance Devices

• The Sporting Conversions Mag Lock
• Checking for a Bullet Button Failure

Troubleshooting an AR-15

• Separated primer within an AR-15 Action
• Replacing a lost nut on the ARMS #40 flip-up sight

Favorite AR Configurations

• Sean Newton's favorites

Available Calibers

• 17 Remington
• 20 Tactical
• 204 Ruger
• 221 Fireball
• 22 Long Rifle
• 5.56mm NATO
• 222 Remington
• 222 Remington Magnum
• 223 Remington
• 223 WSSM
• 6mm Whisper
• 243 WSSM
• 25 WSSM
• 6mm PPC
• 6.5mm Grendel
• 6.5mm PPC
• 6.8mm SPC
• 7mm Whisper
• 300 Whisper
• 338 Spectre
• 9mm Parabellum/Luger/NATO
• 45 ACP
• 450 Bushmaster
• 458 SOCOM
• 475 Tremor
• 50 Beowulf
• 500 Phantom

-- SeanNewton - 28 Jan 2006

Thanks to Viras of Calguns for the Aeroprecision model number