From Novice to Gunsmith: Building an AR-308 with a 308 80% Lower Receiver

Introduction

Building your own AR-308 with a 308 lower receiver 80 percent is a rewarding DIY project for any firearms enthusiast. Whether new to gun building or looking to customize your collection, starting with an 80% lower receiver offers:

• Customization: Create a unique firearm tailored to your preferences.
• Control: Oversee the quality and assembly process yourself.
• Savings: Often cheaper than purchasing a full rifle.

This guide will help you understand and build your AR-308 step-by-step, ensuring you enjoy the process and the result.

Understanding the 308 Lower Receiver 80 Percent

Definition

A 308 lower receiver 80 percent is a partially finished lower receiver for an AR-308 rifle. It is called “80 percent” because it is 80% complete and requires the remaining 20% of the machining process to become a functional firearm component. This final 20% involves milling, drilling, and other modifications to make it capable of housing the trigger, hammer, and other essential parts.

Legal Status

The 308 lower receiver 80 percent is not considered a firearm under federal law. According to the Bureau of Alcohol, Tobacco, Firearms and Explosives (ATF), an 80% lower is officially termed a “receiver blank” and does not require a serial number, background check, or FFL (Federal Firearms License) to purchase. However, once you complete the machining process, it becomes a firearm and is subject to all applicable federal and state laws.

Important Legal Note: Some states have specific regulations regarding 80% lowers. For instance, California requires serialization even for personal builds, and several states like New York and New Jersey have outright bans. Always check your local and state laws before purchasing or completing an 80% lower receiver.

Components Missing

An 80% lower receiver is missing several critical components that you will need to machine yourself. These missing components typically include:

• Fire Control Cavity: The area where the trigger and hammer are housed.
• Pin Holes: Holes for the trigger, hammer, and safety selector pins.
• Trigger Slot: The slot where the trigger passes through the receiver.

By completing these areas yourself, you transform the 80% lower into a fully functional lower receiver that can be assembled with other AR-308 parts to create a complete rifle.

Why Choose an 80% Lower Receiver?

Using an 80% lower receiver offers several benefits:

• Privacy: No serial numbers or FFL paperwork required, ensuring minimal invasion of privacy.
• Customization: You have full control over the parts and features of your build.
• Cost Savings: Avoid manufacturing costs and “brand tax,” making it a cost-effective option.

By understanding these aspects, you’re well-prepared to start your journey in building a custom AR-308 rifle. Next, we will go through the process of choosing the right 308 lower receiver 80 percent for your build.

Choosing Your 308 Lower Receiver 80 Percent

Selecting the right 308 lower receiver 80 percent is crucial for a successful AR-308 build. Here, we’ll cover the key aspects you need to consider: material options, compatibility, and design features.

Material Options

When it comes to materials, you generally have two primary choices: forged and billet aluminum.

• Forged Aluminum: This option is created by hammering aluminum into shape, making it highly durable and strong. It’s often the go-to for those looking for robust, reliable performance.

• Billet Aluminum: Billet lowers are machined from a solid block of aluminum. This process allows for more intricate and customizable designs. While slightly less strong than forged, billet lowers offer unique aesthetic and functional benefits.

Both types are usually made from high-quality aluminum, such as 6061-T6 or 7075-T6, known for their durability and strength.

Compatibility

One of the most important factors when choosing your 308 lower receiver is ensuring compatibility with other parts. The AR-308 platform has several variations, and not all parts are interchangeable.

• DPMS Style: Most 308 lower receivers are designed to be compatible with the DPMS (Defense Procurement Manufacturing Services) pattern. This is the most widely used and offers the most options for parts and accessories.

• AR-10 Style: Less common but still available, AR-10 style lowers have different dimensions and require specific parts.

Make sure your lower receiver is compatible with the upper receiver and other components you plan to use. For instance, a DPMS lower won’t fit an AR-10 upper.

Design Features

Customization is one of the biggest appeals of building your own AR-308. Here are some design features to consider:

• Color and Finish: Many lowers come in a variety of colors and finishes, such as Tungsten Grey, Olive Drab Green, or Burnt Bronze. Choose one that matches your style and needs.

• Additional Features: Some lowers offer extra features like ambidextrous controls, enhanced mag wells, or integrated trigger guards. These can add both aesthetic and functional benefits to your build.

• Coating Options: Anodized finishes provide extra corrosion resistance, while non-anodized (raw) options allow for more customization. If you plan to serialize or engrave the lower, either option will work fine.

Real-World Feedback

Richard D., a verified buyer, praised the fit and finish of his 80% lower, saying it was “very impressive” and he planned to order another. Mark A. noted that even cheaper uppers fit well with the adjustment screw these lowers have.

D.T. highlighted the great customer service and quick shipping, making the overall experience smooth and satisfying. These real-world reviews underscore the importance of choosing a high-quality lower that meets your specific needs.

By considering these factors, you’ll be well on your way to selecting the perfect 308 lower receiver 80 percent for your custom AR-308 build. Next, we will guide you through the step-by-step process of building your AR-308.

Step-by-Step Guide to Building Your AR-308

Building your own AR-308 from a 308 lower receiver 80 percent can be a rewarding experience. Let’s walk through the process step-by-step.

Tools Needed

Before you start, gather all the necessary tools:

• Milling machine or drill press: Essential for removing excess material.
• Drill bits and end mills: Used for drilling holes and finishing the milling process.
• Vise and clamps: To hold your lower receiver securely in place.
• Safety glasses and gloves: Safety first!
• Measuring tools: Calipers and rulers for precision.
• Jig: A jig makes the milling process more accurate and convenient.

Assembly Instructions

1. Read Instructions Thoroughly:
   Start by reading the manufacturer’s instructions. Each 308 lower receiver 80 percent may have slight variations.

2. Secure the Lower Receiver:
   Mount the 80% lower in a vise using clamps. Ensure it doesn’t move during milling.

3. Remove Excess Material:
   Use a milling machine or drill press to remove the specified areas of material. Follow the guidelines provided by the manufacturer.

4. Drill Necessary Holes:
   Drill holes for the trigger assembly, safety selector, and other necessary components.

5. Finish the Trigger Pocket:
   Use a finishing end mill to clean up the trigger pocket and other areas that require additional machining.

6. Clean and Inspect:
   Thoroughly clean the lower receiver and inspect it for any imperfections.

Safety Checks

Safety checks are crucial to ensure your AR-308 is safe and functional:

• Function Check: After assembly, perform a function check. Ensure the trigger and safety selector work correctly.
• Inspect for Flaws: Look for any signs of misalignment or parts that don’t fit properly.
• Lubricate Moving Parts: Proper lubrication ensures smooth operation and longevity.

DIY Tips

1. Practice Patience:
   Completing a 308 lower receiver 80 percent is not a race. Take your time to ensure each step is done correctly.

2. Use a Jig:
   A jig is incredibly helpful. It guides your drilling and milling, ensuring precision and reducing the chance of errors.

3. Safety First:
   Always wear safety glasses and gloves. Metal shavings can be dangerous.

4. Seek Help if Needed:
   Don’t hesitate to reach out to online communities or local gun stores for advice. Many enthusiasts are happy to share their knowledge.

5. Double-Check Measurements:
   Use calipers and rulers to double-check your work. Precision is key to a functional lower receiver.

By following these steps and tips, you’ll be well on your way to building a high-quality AR-308. Next, let’s dive into the finishing and customizing process to make your build truly unique.

Finishing and Customizing Your 308 Lower Receiver 80 Percent

Once you’ve successfully milled and drilled your 308 lower receiver 80 percent, it’s time to add the finishing touches and customize it to your liking. This section will guide you through the final steps, including milling, drilling, finishing touches, and custom engraving.

Milling

Milling is the process of removing excess material to create the necessary cavities and spaces for the internal components of your AR-308. Here’s how to do it:

1. Secure the Lower Receiver: Use a vise and clamps to hold the receiver securely. This prevents movement during milling.

2. Follow Manufacturer’s Instructions: Each 80% lower may have slight variations. Always read the manufacturer’s instructions thoroughly before starting.

3. Use a Milling Machine or Drill Press: Remove material from the specified areas. Precision is crucial, so take your time.

4. Finish the Trigger Pocket: Use a finishing end mill to clean up the trigger pocket and ensure all edges are smooth.

Drilling

Drilling is the next critical step to complete your lower receiver:

1. Select the Right Drill Bits: Ensure you have the correct sizes for the holes needed for the trigger assembly, safety selector, and other components.

2. Use a Jig: A jig helps guide your drill and ensures precision. It’s especially useful for drilling holes for the fire control group.

3. Drill Slowly and Steadily: Rushing can lead to mistakes. Drill slowly to maintain control and accuracy.

Finishing Touches

After milling and drilling, a few finishing touches can enhance the durability and appearance of your lower receiver:

1. Deburr and Clean: Use a deburring tool to remove any sharp edges. Clean the receiver thoroughly to remove metal shavings.

2. Apply a Finish: If your lower is raw aluminum, consider applying an anodized or Cerakote finish. Anodizing adds corrosion resistance, while Cerakote offers a wide range of colors and additional protection.

3. Assemble Lower Parts Kit: Install the lower parts kit, including the trigger, hammer, and safety selector. Ensure all components fit snugly and operate smoothly.

Custom Engraving

Custom engraving adds a personal touch to your AR-308:

1. Choose Your Design: Decide on a design, which could include your name, logo, or a custom serial number.

2. Select an Engraving Service: Many companies offer custom engraving services. Ensure they have experience with firearm components.

3. Legal Requirements: If your state requires serialization, ensure the engraving meets ATF guidelines for depth and size.

Engraving not only adds a unique flair but can also enhance the value and pride in your build.

By following these steps, you can turn your 308 lower receiver 80 percent into a functional and personalized AR-308.

Next, we’ll address common issues you might encounter during the building process and provide troubleshooting tips to help you overcome them.

Troubleshooting Common Issues

Building an AR-308 with a 308 lower receiver 80 percent can be a fulfilling project, but it can also come with its own set of challenges. Here, we’ll address some common issues you might encounter and provide tips on how to overcome them.

Alignment Problems

Alignment issues can cause significant headaches. They often result from improper securing of the receiver during the milling process.

Tips to Fix Alignment Problems:

• Secure Properly: Always use a vise and clamps to hold the lower receiver firmly in place.
• Double-Check Measurements: Use calipers to ensure all cuts and drill holes are precisely placed.
• Use a Jig: A jig helps guide your drilling and milling, ensuring everything lines up correctly. It’s an invaluable tool for maintaining alignment.

Parts Fitting

Parts fitting issues are common, especially when mixing components from different manufacturers.

Tips to Ensure Proper Parts Fitting:

• Check Compatibility: Verify that all parts are compatible with your specific lower receiver model. AR-15 and AR-10 lowers are not interchangeable.
• Test Fit: Before final assembly, test fit all parts to ensure they fit together properly.
• Adjustments: Minor adjustments can often be made with a file or sandpaper to ensure a snug fit. For example, one user mentioned that the front takedown pins were too short when using a Palmetto upper kit. They resolved this by purchasing a matching upper.

Finishing Flaws

Finishing flaws can detract from the appearance and functionality of your rifle.

Tips to Avoid Finishing Flaws:

• Take Your Time: Rushing through the milling and drilling process can lead to mistakes. Take your time and follow the manufacturer’s guidelines.
• Clean Thoroughly: After milling, clean the receiver thoroughly to remove metal shavings and debris.
• Inspect Regularly: Regularly inspect your work for imperfections. Address any issues immediately to prevent them from becoming bigger problems.

Real-World Example:
One builder noted that their charging handle was dragging hard. They resolved this by ensuring the upper and lower receivers were properly matched and by checking for any burrs or rough spots that needed smoothing.

By addressing these common issues with care and precision, you can ensure your AR-308 build is both functional and reliable.

Next, we’ll explore the benefits of building your own AR-308 and why it’s a worthwhile endeavor.

Benefits of Building Your Own AR-308

Building your own AR-308 has numerous advantages that make it an appealing project for both beginners and experienced firearm enthusiasts. Let’s break down the key benefits: cost-effectiveness, customization, and skill development.

Cost-Effectiveness

One of the biggest reasons to build your own AR-308 is the potential to save money. Pre-assembled rifles can be expensive, often costing upwards of $1,000. In contrast, assembling your own can significantly reduce this cost.

For example, using a 308 lower receiver 80 percent from Daytona Tactical, you can source individual components and build a high-quality rifle for a fraction of the price. This cost-saving approach allows you to allocate your budget to other important aspects like optics or additional accessories.

Customization

Customization is another major benefit. When you build your own AR-308, you have the freedom to choose each part to fit your specific needs and preferences.

Barrels: Select from various lengths and materials depending on your shooting requirements.
Handguards: Opt for Picatinny, M-LOK, or Keymod systems to accommodate your preferred accessories.
Lower Receivers: Choose between billet and forged receivers for different aesthetic and functional benefits.

This level of personalization ensures that your rifle is tailored exactly to your liking, something not possible with off-the-shelf options.

Skill Development

Building your own AR-308 is an excellent way to develop technical skills and deepen your understanding of firearms. The assembly process teaches you how each part functions and fits together, enhancing your troubleshooting and maintenance capabilities.

Case Study:
A user from the Shooting Illustrated community shared their experience of building an AR-15 carbine. They highlighted the importance of using painter’s tape to avoid scratching the receiver during assembly. This attention to detail can make a big difference in the quality of your build.

By learning the ins and outs of your firearm, you’ll become more adept at maintaining and upgrading it in the future. This hands-on approach not only enhances your skills but also deepens your connection with your firearm.

Next, we’ll discuss the legal considerations and compliance you need to be aware of when building your own AR-308.

Legal Considerations and Compliance

Building your own AR-308 from a 308 lower receiver 80 percent is an exciting project, but it comes with important legal considerations. You must be aware of state laws, serial number requirements, and ATF regulations to ensure compliance.

State Laws

State laws vary widely when it comes to building firearms. Some states have stringent regulations, while others are more lenient. For instance, states like California, New York, and New Jersey have strict rules that may require serialization and registration of your completed firearm. In contrast, states like Texas and Florida have fewer restrictions.

Remember: Even within states, certain cities like Boulder and Denver in Colorado have their own specific rules. Always check your local regulations before starting your build.

Serial Numbers

Federal law does not require serialization of an 80% lower for personal use. However, if you plan to sell or transfer the firearm, it must be serialized. Some states, like California, mandate serialization even for personal builds.

Key Point: If you hire a licensed firearms manufacturer to complete your 80% lower, they will handle serialization for you.

ATF Regulations

The ATF (Bureau of Alcohol, Tobacco, Firearms and Explosives) classifies an 80% lower as an incomplete receiver, not a firearm. This means you can purchase it without a background check. However, once you complete the machining process, it becomes a firearm, and all federal laws apply.

Important: According to ATF final rule 2021R-05F, you cannot order an 80% lower and jig-related products at the same time. If you have both in your cart, you will not be able to complete the checkout process.

ATF Rules also govern barrel length and overall length for AR pistols. Ensure your build complies with the National Firearms Act (NFA) to avoid creating an illegal SBR (Short-Barreled Rifle).

Compliance Checklist

• Check State and Local Laws: Verify regulations for your area.
• Understand Serialization Requirements: Know when and how to serialize your firearm.
• Follow ATF Guidelines: Ensure your build meets all federal regulations.
• Consult Experts: When in doubt, consult with an attorney or your local ATF representative.

By adhering to these legal considerations, you can build your AR-308 confidently and responsibly.

Next, we’ll answer some frequently asked questions about building an AR-308.

Frequently Asked Questions about Building an AR-308

What tools do I need to complete a 308 lower receiver 80 percent?

To complete a 308 lower receiver 80 percent, you’ll need some basic tools. These include:

• Drill Press or Hand Drill: For drilling precise holes.
• Router: Essential for milling out the fire control cavity.
• Jig Kit: This helps guide your drilling and milling operations.
• Vise: To hold your receiver securely while you work.
• Measuring Tools: Calipers and rulers to ensure accuracy.
• Safety Gear: Eye protection and ear protection are a must.

With these tools, you can transform your 80% lower into a functioning part of your AR-308.

Can I sell a firearm I build from a 308 lower receiver 80 percent?

No, you cannot legally sell a firearm you build from a 308 lower receiver 80 percent. According to the ATF, manufacturing firearms for sale requires a Federal Firearms License (FFL).

“Because there is a grey area of intent when it comes to selling an 80% lower, we do not advise selling your completed lower receiver.” – 5D Tactical

It’s best to build for personal use only to stay on the right side of the law.

How do I ensure my AR-308 is compliant with state laws?

Compliance with state laws is crucial. Here are some steps to follow:

• Research State Laws: Check if your state allows 80% lower builds. States like California, New York, and New Jersey have restrictions.
• Serialization: Some states require serialization. You can engrave a custom serial number on your lower.
• Consult Local Authorities: When in doubt, consult with local law enforcement or an attorney.

By understanding and following these guidelines, you can ensure your AR-308 build is legal and compliant.

Next, we’ll move on to the conclusion and wrap up our guide on building your own AR-308.

Conclusion

Building your own AR-308 from a 308 lower receiver 80 percent is a rewarding experience. It’s not just about having a customized firearm; it’s about the pride that comes from creating something with your own hands.

Project Satisfaction: Many builders find that the process of completing an 80% lower receiver is both educational and fulfilling. From the initial steps of choosing the right materials to the final touches of custom engraving, every stage offers a chance to learn and improve your skills. Plus, knowing that your firearm is unique and tailored to your preferences adds a special touch.

Daytona Tactical: At Daytona Tactical, we understand the passion that goes into these projects. That’s why we offer high-quality 80% lower receivers and parts kits to help you build the AR-308 of your dreams. Our products are designed to be user-friendly, making the building process as smooth as possible for both novices and experienced gunsmiths.

Explore our extensive collection of 80% lower receivers and parts to start your next project today. With our reliable components and detailed guides, you’ll be well on your way to completing a firearm that you can take pride in.

Happy building!