Factory Accessories, Parts and Individual Lower Receivers

In this section you will find accessories sold for the AR-15 that come in Colt factory packaging and Colt AR-15 parts. There will also be information and images of Colt factory individual lower receivers as sold by Brownells and Arms Unlimited.

Part codes:

  • C on bolt carrier: ?
  • C MP on barrel: Colt Magnetic Proofed
  • O on barrel (outside of chamber area): Chrome Lined
  • MPC on bolt: Magnetic Proofed Colt
  • R on barrel (outside of chamber area): Rosco/ESS
  • S on selector lever: Schmidt
  • W on barrel (outside of chamber area): Manufactured by Wilson
  • .4 on barrel extension: Colt
  • .. on barrel extension: Microbest