Yes, finishing an 80% lower is extremely easy. However, that does come with caveat. The lower should absolutely be finished with a jig. Let us start by saying this. It can be done.. but only under the perfect conditions.
There are three main reasons you really shouldn’t do this: precision, time, and safety.
Your Lower Parts Kit Requires Precision
When we say precision, there are a few different things that we are talking about. First, there are some exact measurements that will go into completing your 80% lower. If you’ve never finished a lower before, there are a few specific depth measurements that are involved.
Next, when you’re milling the control pocket, there is some precision required to take out all of the extra material while also leaving the necessary amount of material along the outside. Once again, the jig has this built into it. It couldn’t be any easier. The same could be said for any of the other parts that require drilling or milling.
The 80% Arms Easy Jig Router is the easiest way to machine with an 80% jig and requires little mechanical experience.
An 80% Lower Jig Saves Serious Time
These newer, router-based jigs are extremely fast to finish a lower. If you try to do so without one.. Well, you’ll be at it for awhile. The fact that the jigs are pre-shaped to allow you to only drill exactly where you need to will be extremely helpful.
Additionally, the fact that the pocket is already added into the jig, and you’ll be able to mill it out precisely without having to measure will save you time.
Newer jigs can realistically finish a lower in under an hour. Older jigs take longer. But, both options will be way faster than doing it on your own.
A Quality 80% Lower Jig Means Safety
Lastly, safety is a huge factor to consider. While finishing your lower with a jig doesn’t absolutely guarantee your safety, it will go a long way in improving it. As a reminder, you should always wear safety goggles while milling your receiver.
You'll need quality end mill bits like the ones above. This ensures you're machining safely and quickly.
However, when you’re using a jig, the newer ones will prevent the end mill bit from making contact with the sides of the jig. This will protect you from potential metal dust being thrown at you. However, if you are finishing without a jig, you don’t have this protection. It is safer to move a router around the jig than it is to move the jig around a drill press.
The jig will also give you a little financial protection. When you’re using the jig, there’s not much that can go wrong, so you aren’t wasting your money on a lower receiver.
Make it Easy, Get The 80% Lower Jig
Unless you are an extremely talented machinist with a wider variety of tools, you can finish even a tough, forged 80% lower on your own using an 80% lower jig. You can probably find some schematics online, and potentially finish it yourself. However, if you’re anyone else, a jig is absolutely the way to go. Even if you are an experienced machinist, using a jig will save you time and give you more guaranteed measurements.DISCLAIMER: If you are new to the world of DIY AR-15 building, you likely have a lot of questions and rightfully so. It’s an area that has a lot of questions that, without the correct answers, could have some serious implications. We are by no means providing this content on our website to serve as legal advice or legal counsel. We encourage each and every builder to perform their own research around their respective State laws as well as educating themselves on the Federal laws. When performing your own research, please be sure that you are getting your information from a reliable source.