Expo Arms 6mm ARC / 6.5 Grendel Type II - Bolt Assembly

The Expo Arms 6mm ARC / 6.5 Grendel Type II Bolt Assembly is a complete replacement bolt assembly machined from 9310 steel and finished in black nitride, designed for AR-15 platforms chambered in 6mm ARC or 6.5 Grendel Type II.

For precision and competition shooters pushing high round counts, the quality of the bolt matters more than almost any other component in the build:

9310 steel construction for long service life: 9310 is a high-strength alloy steel known for its toughness and fatigue resistance under sustained high-pressure cycling — making it a preferred bolt material for precision and competition builds.

Black nitride finish for wear and corrosion resistance: The black nitride surface treatment penetrates the steel rather than sitting on top of it, delivering a harder surface that resists wear at the locking lugs and bolt face without adding dimensional thickness that could affect headspace or fit.

Compatible with both 6mm ARC and 6.5 Grendel Type II: The shared bolt face geometry between 6mm ARC and 6.5 Grendel Type II means this single assembly serves both chamberings.

• Type: Bolt Assembly
• Caliber Compatibility: 6mm ARC, 6.5 Grendel Type II
• Material: 9310 steel
• Finish: Black nitride
• Compatible Platform: AR-15

Compatible with standard AR-15 bolt carrier groups and upper receivers chambered in 6mm ARC or 6.5 Grendel Type II.

An ideal bolt assembly for precision AR-15 builds chambered in 6mm ARC or 6.5 Grendel Type II, competition rifles requiring long service life between replacements, and builders seeking a quality-inspected bolt for a demanding long-range platform.

Expo Arms delivers mil-spec and performance AR-15 components at competitive prices without compromising quality. Backed by Expo's Limited Lifetime Warranty against defects in materials and workmanship.