Building your own AR-15 or AR-10 from an 80% lower receiver is an exciting and rewarding experience, but selecting the right AR build kit is just as important as finishing your lower. A quality build kit includes the upper receiver, barrel, bolt carrier group (BCG), handguard, and other essential components to complete your firearm. When paired with your 80 percent lower, the right kit can make all the difference in terms of performance, durability, and customization.
In this article, we’ll explore some of the best AR build kits available, why they’re worth considering, and how to pick the perfect one for your next build.
What’s in an AR Build Kit?
An AR build kit typically includes everything you need to assemble your firearm, except the lower receiver. Here’s what you’ll commonly find in a kit:
- Upper Receiver (Assembled or Unassembled): Includes the ejection port cover, forward assist, and sometimes the barrel.
- Barrel: Available in different lengths and profiles depending on your needs.
- Bolt Carrier Group (BCG): The heart of the rifle, responsible for cycling rounds.
- Handguard: Protects your hands and provides attachment points for accessories.
- Gas System: Includes the gas block and tube for proper cycling.
- Muzzle Device: Flash suppressor, muzzle brake, or compensator.
Some kits may also include a lower parts kit (LPK) with the trigger, safety selector, magazine catch, and other small components.
The Benefits of Pairing an AR Build Kit with Your 80% Lower
1. Ease of Assembly
By starting with an 80 percent lower receiver and an AR build kit, you streamline the process of creating a complete firearm. Build kits are designed to be user-friendly, with parts that are compatible and ready to install.
2. Cost Savings
Purchasing a complete build kit is often more affordable than buying each part individually. You also avoid paying for assembly labor, which is already handled in pre-built rifles.
3. Customization Options
AR build kits come in a wide range of configurations, letting you choose everything from the caliber to the barrel length and handguard style. You can pair the kit with your 80 lower receiver for a fully custom build that suits your needs.
The Best AR Build Kits to Consider
Here are some top AR build kits to pair with your 80% lower receiver, based on quality, reliability, and value:
1. Palmetto State Armory (PSA) AR Build Kits
Why It’s Great: Palmetto State Armory is a trusted name in the AR world, known for offering high-quality kits at budget-friendly prices.
- Features:
- Multiple caliber options (.223/5.56, .300 Blackout, 9mm, etc.).
- Assembled or unassembled uppers.
- Nitride-treated barrels for durability.
- Best For: Builders looking for reliable, cost-effective kits for their first or fifth build.
2. Aero Precision M4E1 Build Kits
Why It’s Great: Aero Precision is a favorite among firearm enthusiasts for its precision-machined components and sleek designs.
- Features:
- Enhanced M4E1 upper receiver for improved durability.
- High-quality barrels in various lengths and profiles.
- Free-float handguards for better accuracy.
- Best For: Builders who want premium components and a clean, professional look.
3. Thunder Tactical AR Build Kits
Why It’s Great: Thunder Tactical offers kits specifically designed to pair with 80% lower receivers, ensuring seamless compatibility and easy assembly.
- Features:
- Complete kits with everything you need, minus the lower receiver.
- Affordable options without compromising quality.
- Available in multiple calibers, including 5.56, .300 Blackout, and .308.
- Best For: Builders who want reliable kits at an excellent price point.
4. BCM (Bravo Company Manufacturing) Build Kits
Why It’s Great: BCM is renowned for its military-grade components, making it a top choice for serious builders.
- Features:
- Chrome-lined barrels for increased longevity.
- Lightweight KeyMod and M-LOK handguards.
- High-performance bolt carrier groups.
- Best For: Builders focused on tactical applications or high-performance builds.
5. CMMG AR-9 Build Kits
Why It’s Great: If you’re building an AR-9, CMMG’s kits are among the best for pistol-caliber carbines (PCCs).
- Features:
- Dedicated 9mm components for smooth cycling.
- Lightweight and compact designs.
- Reliable bolt carrier groups for PCC builds.
- Best For: Builders creating a compact, close-quarters AR-9.
How to Choose the Right Build Kit for Your 80% Lower
1. Determine Your Purpose
Think about what you’ll use the firearm for:
- Home Defense: Look for shorter barrels (10.5–16 inches) and lightweight components.
- Hunting or Long-Range Shooting: Consider longer barrels (18–20 inches) and free-float handguards for accuracy.
- Range Fun: A basic kit with a standard barrel and upper will do the trick.
2. Match Caliber to Your Needs
- .223/5.56: The most popular AR-15 caliber, versatile for most applications.
- .300 Blackout: Great for suppressed builds or short-barreled rifles (SBRs).
- 9mm: Ideal for AR-9 builds, offering low recoil and affordable ammo.
3. Consider Your Budget
AR build kits range from budget-friendly to high-end. Decide how much you’re willing to spend and prioritize components like barrels and bolt carrier groups for the best performance.
4. Ensure Compatibility
Always double-check that the build kit is compatible with your 80% lower receiver. Some platforms, like AR-10s or AR-9s, require specific components that differ from the AR-15 standard.
Tips for a Smooth Build
- Use Quality Tools: Invest in a good armorer’s wrench, torque wrench, and punch set to make assembly easier.
- Follow Instructions: Many build kits come with step-by-step guides or online tutorials. Take your time and follow them closely.
- Test Your Build: Before heading to the range, perform a safety check and function test to ensure everything operates correctly.
Final Thoughts
Pairing your 80% lower receiver with the right AR build kit is key to creating a firearm that’s reliable, functional, and tailored to your needs. Whether you’re building an AR-15, AR-10, or AR-9, there’s a kit out there that will suit your purpose and budget.
Ready to start your next project? Check out Thunder Tactical for high-quality 80% lowers, AR build kits, and all the tools you need to build the firearm of your dreams. Let’s get building!