How To Build An AR15

Trying to learn how to build an AR15? Well, first things first, you’ll need an extensive AR-15 assembly kit, preferably one that comes with both upper and lower receivers, a handrail, barrel, and stock, plus grips, forward assists, port covers, charging handle, and all those small buffers and tubings that come along for the ride too.

It may sound like a handful of pieces and parts, but trust us, you can stop scratching your head. Building any weapon does sound like a task better suited for a gunsmith, or someone with at least some kind of mechanical ability. But just because you hear that, doesn’t always make it true.

In fact, with the correct assembly kit, crafting any firearm is not just achievable, but actually pretty easy. For the most part, it’s just knowing which parts fit into where, like an incarnation of the jigsaw puzzle. The only component that may require some further expertise, is the 80% lower receiver we sell in our kits.

What is an 80 lower receiver?

Essentially, it’s exactly what it sounds like. As a way to circumvent ATF licensing and serialization, manufacturers started producing, and selling, lower receivers as “incomplete” goods. Basically, the biggest difference between an 80% lower and its fully-operational counterpart, is that the former isn’t fully milled to add the trigger control group.

Using our kits, you can build the entire weapon up until the point where you insert the pistol grip and trigger unit. Milling an 80% lower is left to the customer, but with recent advances in technology and the widespread availability of machinery, the process isn’t difficult.

Some Brief Methods On How to Finish an 80 Percent Lower


For the sake of time, we advise you seek out professional help when trying to determine the actual drilling locations; something we can provide for you. Milling a receiver requires some preparation too, you’ll need a lower receiver jig, a variety of different sized drill bits, a Dremel, and a drill press. If you’re able to assemble all of that, then great, you’re on your way to a fully-functioning weapon. However, acquiring the right tools can prove exhausting and expensive, which is why we recommended seeking out a third-party provider.

Below, you’ll find 5 approaches that any individual can theoretically try. Some may be more complicated or infeasible, but nonetheless, we just wanted to provide all methods.

  1. CNC Machine: An automated machine tool controlled by computer design and manufacturing systems that offer a much closer and precise drilling option. It eliminates any level of human error, but also requires adequate knowledge of computer operating systems
  2. Milling Machine: One of the more commonly selected options, milling machines can be operated manually, or through computer systems similar to a CNC machine. They offer precision drilling, but if operating it yourself, there may be a steep learning curve. It will essentially perform similar to the CNC, but they’re more widespread.
  3. Drill Press: A pedestal styled drill, this press is much easier to use than our previous entries, and does not require a ton of practical skill. Most gun builders will use this method since drill presses are economical and extremely easy to find. The drawback is that you typically won’t get the same level of precision drilling as a CNC or Milling Machine.
  4. Router: Designed to hollow-out the edges of solid materials, a router uses a single spindle and rotates extremely quickly to perform its job. Much like the drill press, it’s easy to use but does require some pre-existing experience. Since the router moves so quickly, builders must be sure not to “over-drill” the actual receiver.
  5. Electric Hand Drill: While hand drills will get the job done, they’re mostly considered “last case” scenario type tools. The hand drill’s nature does not allow for precision drilling or depth settings, but they are available virtually anywhere, and they don’t require experience to use.

We hope that this was informative enough to get you started on milling your own lower receiver and getting your weapon full-functional. If you’re interested in purchasing your own 80% lower, or any of our assembly kits, then please head over to our products page and check out our inventory today!