Expo Arms 5.56 NATO Bolt Assembly - Nitride

The Expo Arms 5.56 NATO Bolt Assembly is a mil-spec AR-15 bolt assembly finished in salt bath nitride, featuring pre-installed gas rings and an extractor with Crane O-ring for reliable extraction and cycling on 5.56 NATO and .223 Rem platforms.

A quality bolt assembly is the heart of your BCG — the Expo Arms 5.56 NATO Bolt Assembly delivers the components and construction that keep it running:

Salt bath nitride finish for durability and corrosion resistance: Nitride treatment penetrates the surface of the bolt rather than coating it, resulting in a harder, more wear-resistant finish that maintains tight tolerances better than phosphate over extended use. It also provides superior corrosion resistance for shooters operating in wet or humid conditions.

Pre-installed gas rings for immediate reliability: Gas rings come pre-installed to factory spec, ensuring proper bolt carrier seal out of the box without requiring the shooter to source or seat rings separately before assembly.

Crane O-ring extractor insert for positive extraction: The extractor insert with Crane O-ring provides consistent extractor tension for reliable case extraction across a wide range of 5.56 NATO ammunition — reducing the risk of failures to extract that can result from a weak or worn extractor spring.

Mil-spec dimensions for universal AR-15 compatibility: Machined to standard mil-spec dimensions, this bolt assembly is a direct-fit replacement or upgrade for any standard AR-15 bolt carrier group.

• Type: Bolt Assembly
• Caliber: 5.56 NATO / .223 Rem
• Finish: Salt Bath Nitride
• Spec: Mil-Spec
• Gas Rings: Pre-installed
• Extractor: Includes extractor insert with Crane O-ring
• Compatible Platform: AR-15

Compatible with standard AR-15 mil-spec bolt carrier groups and upper receivers chambered in 5.56 NATO and .223 Rem. Direct drop-in fit for any standard AR-15 BCG body.

Expo Arms delivers mil-spec AR-15 components at competitive prices without compromising quality. Made in the U.S.A. and backed by Expo's Limited Lifetime Warranty against defects in materials and workmanship.