Your 5.56/.223 bolt carrier group (BCG) is more than just a part – it’s the heart of your AR-15. Whether you’re building from scratch or upgrading your existing rifle, choosing the right BCG ensures reliability, smooth cycling, and long-term performance.

At Mounts Plus, we offer a battle-ready selection of full auto (M16-style) 5.56/.223 BCGs in finishes like Nickel Boron, Black Nitride, and Phosphate—all from trusted brands like Fail Zero, WMD Guns, Sons of Liberty Gun Works, Aero Precision, and more.

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⚙️ Why a Dedicated 5.56/.223 BCG Matters

The 5.56 NATO and .223 Remington cartridges may look similar—but your bolt carrier group must meet mil-spec standards to handle the pressures of both. That’s why our BCGs are built with:

• 8620 steel carriers and 9310 or Carpenter 158 bolts

• Magnetic Particle Inspection (MPI) and shot peening for strength

• Properly staked gas keys for long-term reliability

• Drop-in compatibility with all mil-spec AR-15 uppers

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🔧 Choose the Right BCG for Your AR-15

We carry BCGs tailored to your preferences, shooting style, and budget:

🔹 Nickel Boron (NiB) 5.56 BCGs

• Ultra-slick finish for low-friction operation

• Easier to clean—wipes down with a cloth

• Runs cleaner with less lubrication

• Ideal for suppressed rifles

🔹 Black Nitride BCGs

• Corrosion-resistant and long-lasting

• Smoother than phosphate, more affordable than NiB

• Great all-purpose option

🔹 Phosphate Coated BCGs

• True mil-spec look and feel

• Proven durability in harsh conditions

• Budget-friendly and combat-proven

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🔥 Built for Every Use Case

• ✅ Tactical or duty-ready rifles

• ✅ Competition and 3-gun builds

• ✅ Hunting setups

• ✅ Suppressed and SBR platforms

• ✅ Recreational and training rifles

All of our BCGs are drop-in ready, backed by manufacturers we trust, and ship fast from our U.S. warehouse.

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💡 Compatible With

• AR-15 uppers chambered in 5.56 NATO, .223 Rem, and .223 Wylde

• Mil-spec lower receivers

• Direct impingement gas systems (carbine, mid-length, rifle)

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❓ FAQ:

Is a full auto BCG legal in my AR-15?

Yes. A full auto (M16-profile) BCG is 100% legal in civilian AR-15s. It does not make your rifle fully automatic—it simply adds mass and improves cycling.

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Can I use this BCG in a .223 Wylde barrel?

Absolutely. All BCGs listed are compatible with 5.56 NATO, .223 Remington, and .223 Wylde chambers.

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What’s the benefit of a Nickel Boron BCG over Nitride?

Nickel Boron is smoother, easier to clean, and often lasts longer. Nitride is more affordable and corrosion-resistant. It depends on your use case.

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Are these BCGs MPI tested?

Yes. Many of the BCGs we carry are MPI (Magnetic Particle Inspected) and shot-peened to meet or exceed mil-spec standards.

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Will these fit any AR-15 upper?

Yes. As long as your upper is mil-spec and chambered in 5.56/.223/.223 Wylde, these BCGs will drop in without issue.

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🚀 Upgrade Your AR-15 with a Proven 5.56/.223 BCG

Whether you're building a new rifle or improving your current setup, the right 5.56/.223 BCG can make all the difference. From Nickel Boron coated carriers to MPI-tested bolts, we stock components trusted by professionals and enthusiasts alike.

Shop now—ships fast. Built to run.