Novice-to-Novice: AR15 Lower Receiver Build – American Made Tactical

Lower milling American Made Tactical


A few months ago we received a lot of interest in the process of building a firearm. We thought long and hard about going through the paces of a building a firearm, seeing as we are complete novices. It dawned on us, if a novice shows the problems, maybe they can be avoided. So, we jumped on the AR15 bandwagon and got to work.

Now, before anyone attempts to build a gun there are a few considerations to make. The first is cost. Building a firearm is much more expensive than actually purchasing one. Even buying an unfinished lower receiver is about the same price as buying a complete one. When building, we quickly learned that it isn’t about saving time or money but about really making it your own.

The second consideration is ability. While it may not be extremely difficult for someone mechanically inclined it can be challenging with no prior experience. One mistake can make a firearm incredibly unsafe to operate. If you aren’t a stickler for details than building a firearm may not be for you.

The last major consideration, when deciding to build a firearm, is why. If you are building one to stay off the grid, look elsewhere to learn. We do not promote building firearms in order to ‘pull one over’ on the government. If you want to make something you are a part of and proud of, this is the type of article for you. Building your own firearm deserves bragging rights and gives a builder an incredible sense of accomplishment.

Lower Receiver Considerations:

According to the ATF, a firearm is the lower receiver. In most rifles, the lower receiver and upper receiver can be made from the same piece of metal, or polymer. Building a firearm that requires a one-piece receiver is not only extremely difficult, but requires extensive knowledge and tools. About 15 years ago companies started making lower receivers that needed to be milled or have pieces removed, in order to not be considered a firearm.

Why AR15? Well, it’s simple. The AR15 platform is modular, meaning, the lower receiver is a completely separate piece from the upper receiver. This gives us a few advantages. There is no need for a plethora of tools or skills in order to produce or manufacture a lower receiver. In addition, you can quickly change the upper receiver (or lower receiver) if you run into any problems. This changing of the upper receiver also allows users to change the caliber of weapon they have. An AR15 can come in a 5.56/223, .458 big bore, 6.5, 6.8, 300 Blackout, 7.62×39, as well as a few odd-ball calibers. While the .308 looks similar to the AR15, the lower receiver has different dimensions making this caliber an AR10 rifle. Keep an eye out for our possible, future AR10 build.

When starting with an AR15 lower build the first consideration is material. Lowers are manufactured in either aluminum or polymer. Polymer is usually used when weight is a strong factor in the type of hardware you put into a rifle. It also is more scratch resistant than aluminum. Aluminum is considered to be a stronger material and can withstand some extreme weather conditions and heat, without sacrificing durability. Each have their own pros and cons.

Our Build

American Made Tactical

As we started this series we wanted to offer options for our readers (that’s you!) and decided to have multiple different receivers in comparable materials and costs. We aren’t trying to create competition, but we do want to offer an alternative option if you aren’t happy with another company. Another polarizing reason we wanted to showcase American Made Tactical was to make a 100% American made rifle.

American Made Tactical is a good price, a high-quality company that produces and sells only American Made products. Even the springs they carry in their LPK (lower parts kit) are 100% American made. While this may seem trivial the more companies that produce and buy from American Companies and manufacturers, the better the American economy will become.

In addition to this USA only product is a bulk purchase option in both billet and forged lowers. For an example, 80% arms will sell you 10 anodized, billet lower receiver for $70 each (normally $90) coming to ~$700. American Made Tactical offers 10 anodized, billet lower receivers for $690 or anodized, forged for as low as $450.

American Made Tactical also offers a jig system which is eerily similar looking to 80% Arms Gen 1 jig system. There are definitely some major differences between the two, but it is worth mentioning that the jig system would be used nearly the same way. Unfortunately, American Made Tactical did not offer to supply a jig for us to review so we are not able to give a complete review of their lower with their build.

The Build

Jig System and Lower

Because of our lack of major milling tools, we felt it best to use our 80% Arms Jig with the American Made Tactical billet receiver. It fit like a glove with no major issues. There were some differences between the AMT (American Made Tactical) and 80% Arms lowers that may be important to some users.

AMT offers an engraved F/S for the fire selector while 80% only offers an engraved fire/safe fire selector. We received an engraved F/A AMT lower receiver with their 100% American manufactured LPK (lower parts kit) minus the buffer tube assembly and stock.

Additional Tools

There is no need to add tools outside of what we used for our original router jig builds. The 80% Arms jig fit perfectly with little to no error in fit and we were excited to give this lower receiver a once over.


Following the same direction and use as laid out by the 80% Arms directions we got to use on the pilot hole drilling of the AMT lower receiver. In our past article, we spoke about the difficulty of using a battery operated drill for this.

With the addition of the AMT receiver, we found that the AMT receiver seemed like a much stronger aluminum. We might be able to say it was poor power consumption on the drill or lack of experience, but in our opinion, the receiver was a harder, or more dense, aluminum.

In addition to the dense material we again decided to forego the cutting fluid, which may have made more difficulties than necessary. Whatever the reason, it’s not a negative. The dense material will most likely hold up better over extended use and abuse. In total, the drilling took about 4 hours using 2 drills, 4 batteries, and constant charging.


Moving straight to the milling, we pulled out our Ridgid 2401 Router, set up the router plate, and continued on. Learning from our past build the depth was set to a very shallow initial cut and we increased the PRM. It continually cut like butter.

We learned more than we thought we did during the first build and it seemed to improve the quality and time during our AMT build. During the milling, we were able to adjust the router without turning it off and restarting, as well as using the shop vac to keep the majority of aluminum shaving at a safe distance. We were happy with how things were going.

Now, any good story obviously has to have some kind of issue to make it worth the effort. And so, after an hour of milling, we ran into our first issue, the chuck. Once again the chuck loosened itself up while running making the big shake and slam against the side of the fire control pocket. No major damage but we learned to check the bit more often. As we examined the bit for the damage it appeared as if the bit itself had a broken edge. Could this be why the bit came loose? Examining the cuts inside the receiver led us to discover a poorly cut surface. While not detrimental to the use of the receiver it was still not what we wanted or anticipated.

Could this be why the bit came loose? Examining the cuts inside the receiver led us to discover a poorly cut surface. While not detrimental to the use of the receiver it was still not what we wanted or anticipated.

Setting up the router again we continued on and began to move a bit faster. The noise started to change from a deep cutting/grind with a high pitched mechanical whir to a high pitched grind. The cutting speed seemed to slow down despite the increased RPM on the router. We stopped our work and looked closely at the cutting bit.

This time, it looked as if all three cutting edges had come off, but in reality, we were moving so quickly that aluminum had softened from the heat and compacted itself into the grooves of the router bit. Carefully working it out with a screwdriver the bit came out clear again and we continued on.

Now, we aren’t 100% sure what caused the aluminum to set to the router bit, but we think it was a combination of 3 things:

  • Heat. The increased RPM caused more friction and produced more heat, making the aluminum shavings soft.
  • Harder aluminum. This made more friction and also helped to produce additional heat.
  • Lack of cutting fluid. The fluid is to reduce the amount of friction and since we did not use it with our previous build we thought it unnecessary during this build.

So, we moved forward and reduced our cutting depth, even more, slowed our speed, and added a liberal amount of WD40 to the fire control pocket. Roughly 20 minutes later we were done!

Final Drilling

Again, this part isn’t worth mentioning. However, we wish we had covered the sides with tape before we put it into the jig. As we drilled the safety switch hole and trigger pin holes we caught a lot of shavings mixed with WD40. While not horrible it did scratch the surface a bit, especially by the Safety Selector hole.


AMT made an incredibly strong and durable receiver. Their prices are very competitive and selling only American produced and manufactured products should put them at the top of many people’s lists. Realistically, you can get everything you need directly from them, excluding the router itself. Even if you have already tried another jig system these receivers are well worth the effort and time.

The Positives:

  • Comparable pricing as single units or bulk.
  • Offers both billets and forged lower receivers.
  • Produces their own jig system (we did not use their jig/router system).
  • Possible router milling (although we did not use their jig/router system).
  • Option to come engraved or not engraved.
  • 100% American Made and can prove it!

The Negatives:

  • Deep holes need to be cleaned out frequently.
  • Due to the strength of the aluminum, it was more difficult to drill and mill compared to others (that is not really a negative, but we felt we needed to add to the list).

Keep an eye out for our next part of the build; Installing the LPK into an American Made Tactical AR15 lower receiver.

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Jonathan Kilburn is a Martial Arts Instructor, Special Needs educator and businessman. He focuses on self-reliance and survival in difficult urban and sub-urban areas. Natural disasters have pushed Jonathan to teach about urban farming, homesteading, and survival. As a Special Needs Educator, Mr. Kilburn has developed a neurological approach to executive function. This means: pushing the boundaries of human needs vs human wants. This mindset and philosophy assists in training himself and others in self-reliance and survival. Mr. Kilburn has also studies martial arts which include but are not limited to: Aikido, Combat Sambo, Judo, TaeKwon-Do, Haidon Gumdo, and various other sword arts.


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