How To Complete An 80% Lower Receiver

Completing an 80% lower receiver takes time. This labor can be heavily supplemented with the help of a jig. All it takes is a bit of know how, the right tools, and patience. And, today, our article is bringing you all the know how you need.

Here are the steps to follow in order to complete your 80% lower receiver.

The Right Tools

Having the right tools and bits is the most important factor in completing an 80% lower receiver. Better instruments produce a better quality finish. Here is a list of everything you will need to complete your 80% lower receiver:

• 80% Lower Jig (click here to view our complete list of jig kits)
• Drill press and vise
• Dremel ¼” grinding head
• ⅜” End Mill
• Drill bits 5/16”, ⅜”, 5/32”

Assemble the jig first by connecting plates A and B. Install the VA-C top plates, keeping in mind the location of the jig and the position of the trigger.

The top plate C is marked 1-¼” deep. Set the drill press accordingly, as this is the profile you will be using to make your cuts.

Web Removal

Using a ⅜” end mill, create a flat bottom, making sure to get out all of the “webbing” produced by the first assembly. This should open the pocket and complete that 1-¼” depth needed to complete the 80% lower receiver.

VA-D Drilling

Complete the same actions with the VA-D top plate, using a ⅜” drill bit and a ⅜” end mill. Be mindful of the webbing, and use the end mill to open the pocket to the correct depth.

Trigger Slot

Switch to the 5/16” drill. Drill carefully through the fire control group at the specified hole. Watch for “drill walk” and use a file or the ¼ grinding head Dremel to create a nice finish.

Side Plates A & B

This step is pretty straightforward, but requires more technical skill to produce the best outcome. Instead of drilling all the way through on one side, make your drill holes partially on either side.

This reduces the chance of drill walk.

Complete But Not Finished

Now that you have assembled your 80% lower receiver, use the Dremel to create a nice finish. Once that is done, you have finished your 80% lower.
Here at Thunder Tactical, we are dedicated to providing the best service possible to give you the tools you need to create your dream firearm. Visit us today to get the best quality parts and kits!