5 Ways To Build A Bcm Lower Complete

Building a BCM lower complete can be a fun and rewarding experience, especially for those who are passionate about firearms. However, it requires careful planning, attention to detail, and a solid understanding of the components involved. In this article, we'll explore five ways to build a BCM lower complete, including the necessary tools, materials, and steps to ensure a successful build.

The Importance of Building a BCM Lower Complete

A BCM lower complete is a critical component of a firearm, serving as the foundation for the upper receiver and providing the necessary housing for the fire control group. Building a BCM lower complete requires careful attention to detail, as the lower receiver must be machined to precise specifications to ensure proper function and safety.

What is a BCM Lower Complete?

A BCM lower complete is a type of lower receiver designed for use with AR-15 firearms. It is a critical component of the firearm, providing the necessary housing for the fire control group, magazine well, and buttstock. The BCM lower complete is known for its exceptional quality and durability, making it a popular choice among firearms enthusiasts.

Tools and Materials Needed

Before starting the build process, it's essential to gather the necessary tools and materials. Here's a list of what you'll need:

• BCM lower receiver
• Fire control group (FCG)
• Magazine well
• Buttstock
• Pistol grip
• Safety selector
• Trigger
• Hammer
• Spring and detent pins
• Lower receiver extension
• Endplate
• Castle nut
• Buffer tube
• Buffer spring
• Buffer
• Tools:
  • Torque wrench
  • Allen wrench
  • Punch set
  • Drill press (optional)
  • Safety glasses

Method 1: Building a BCM Lower Complete with a Pre-Machined Receiver

One of the easiest ways to build a BCM lower complete is to start with a pre-machined receiver. This eliminates the need for machining and ensures that the receiver is properly aligned and dimensioned.

Here's a step-by-step guide to building a BCM lower complete with a pre-machined receiver:

1. Assemble the fire control group (FCG) by installing the trigger, hammer, and safety selector.
2. Install the magazine well and buttstock.
3. Attach the pistol grip and safety selector.
4. Install the lower receiver extension and endplate.
5. Assemble the buffer tube and buffer spring.
6. Install the buffer and buffer spring.
7. Torque the castle nut to secure the buffer tube.

Method 2: Building a BCM Lower Complete with a Raw Receiver

Building a BCM lower complete with a raw receiver requires more time and effort, as it involves machining the receiver to precise specifications. However, this method provides the most flexibility and allows for customization.

Here's a step-by-step guide to building a BCM lower complete with a raw receiver:

1. Machine the receiver to precise specifications using a drill press or milling machine.
2. Assemble the fire control group (FCG) by installing the trigger, hammer, and safety selector.
3. Install the magazine well and buttstock.
4. Attach the pistol grip and safety selector.
5. Install the lower receiver extension and endplate.
6. Assemble the buffer tube and buffer spring.
7. Install the buffer and buffer spring.
8. Torque the castle nut to secure the buffer tube.

Method 3: Building a BCM Lower Complete with a 80% Receiver

Building a BCM lower complete with an 80% receiver is a popular method for those who want to save money and avoid machining. The 80% receiver is pre-machined to 80% completion, leaving the final 20% for the builder to complete.

Here's a step-by-step guide to building a BCM lower complete with an 80% receiver:

1. Complete the machining process using a drill press or milling machine.
2. Assemble the fire control group (FCG) by installing the trigger, hammer, and safety selector.
3. Install the magazine well and buttstock.
4. Attach the pistol grip and safety selector.
5. Install the lower receiver extension and endplate.
6. Assemble the buffer tube and buffer spring.
7. Install the buffer and buffer spring.
8. Torque the castle nut to secure the buffer tube.

Method 4: Building a BCM Lower Complete with a Forged Receiver

Building a BCM lower complete with a forged receiver is a more complex method that requires specialized tools and expertise. However, this method provides the strongest and most durable receiver possible.

Here's a step-by-step guide to building a BCM lower complete with a forged receiver:

1. Forge the receiver using a hydraulic press or forging machine.
2. Machine the receiver to precise specifications using a drill press or milling machine.
3. Assemble the fire control group (FCG) by installing the trigger, hammer, and safety selector.
4. Install the magazine well and buttstock.
5. Attach the pistol grip and safety selector.
6. Install the lower receiver extension and endplate.
7. Assemble the buffer tube and buffer spring.
8. Install the buffer and buffer spring.
9. Torque the castle nut to secure the buffer tube.

Method 5: Building a BCM Lower Complete with a 3D Printed Receiver

Building a BCM lower complete with a 3D printed receiver is a cutting-edge method that requires specialized equipment and expertise. However, this method provides unparalleled customization and flexibility.

Here's a step-by-step guide to building a BCM lower complete with a 3D printed receiver:

1. Design and print the receiver using a 3D printer.
2. Post-process the receiver to remove any excess material.
3. Assemble the fire control group (FCG) by installing the trigger, hammer, and safety selector.
4. Install the magazine well and buttstock.
5. Attach the pistol grip and safety selector.
6. Install the lower receiver extension and endplate.
7. Assemble the buffer tube and buffer spring.
8. Install the buffer and buffer spring.
9. Torque the castle nut to secure the buffer tube.

Gallery of BCM Lower Complete Builds

BCM Lower Complete Image Gallery

What is a BCM lower complete?

+

A BCM lower complete is a type of lower receiver designed for use with AR-15 firearms.

What tools and materials do I need to build a BCM lower complete?

+

See the tools and materials section above for a comprehensive list.

Can I build a BCM lower complete with a raw receiver?

+

Yes, but it requires specialized tools and expertise.

Can I build a BCM lower complete with a 3D printed receiver?

+

Yes, but it requires specialized equipment and expertise.

What is the best way to build a BCM lower complete?

+

The best way to build a BCM lower complete depends on your level of expertise and desired level of customization.

We hope this article has provided valuable insights and guidance on building a BCM lower complete. Whether you're a seasoned firearms enthusiast or just starting out, building a BCM lower complete can be a rewarding and challenging project. Remember to always follow safety guidelines and local laws and regulations when building and using firearms.