• Heat treated per Mil-Spec Requirements
  • Shot Peened per Mil-Spec Requirements
  • MPI Tested


Bolt Assembly:

  • Caliber: 5.56 NATO / .223 Rem / 300 Blackout
  • Material: Carpenter 158 Steel
  • Finish Nickel Boron


  • Material: Aircraft Quality E4140 Steel
  • Finish Manganese Phosphate


  • AR-15


When it comes to critical parts like the AR-15 bolt, always stick with a company you can trust such as American Build Arms (AB Arms). Their nickel boron coated AR-15 bolt is the perfect centerpiece for your bolt carrier group.

AB Arms has precision machined it to fit the upper receiver perfectly and function with lasting reliability. The bolt is machined to exact tolerances, heat treated, and shot peened to prepare it for the rigors of law enforcement, military, and competitive shooting use.

What takes this bolt to the next level is the nickel boron coating. This does much more than just protect the metal; it also imparts a natural lubricity to the bolt, enabling it to run smoother even with sparse lubrication. This lubricity also repels fouling, which reduces the time and effort that you have to put into cleaning.

Have a question?

Ask an Expert