by Rifle Guard | 10:25 pm

So you have finally decided to take on building your own AR-15, you head on over to 80% Lowers, or AR-15 Lower Receivers, and you see that there are multiple options. It might seem a bit difficult to choose at first, deciphering which type is overall best for your particular build. But you will find that making the choice is a lot easier than you might think at first glance. Thankfully!

You might think, at first, why the heck are there so many different types of aluminum to choose from, why not one? Well, it comes down to history. The first lowers were cast, and subsequent varieties were then derived from this first option.

Cast Aluminum Lowers

Cast aluminum is a process by which the lower the created from a mold, in an assembly line fashion. This original design was so popular because they were easily created in mass production plants, especially in times of war, when creating weapons quickly. Time of course, is of the essence, so this particular method was popular due to the ease of manufacturing the parts.

Beyond the ease, the cast aluminum process tended to be a much more economic choice because it took far less time to create parts in this fashion.

Though, the quality of the cast often came into question, from a few manufacturers who made millions off of bum parts that broke easily due to poor manufacturing.

Billet Aluminum Lowers

Billet Aluminum lowers are created from rolled metal, that is then cut from ‘bar stock’ and formed into the proper shape and size. From that point, it is then taken to a CNC machine for cutting out the pieces to allow the lower to be functional.

Billet lowers are regarded as the most ‘pretty’ receivers because with the CNC machining they can be designed however you like, with added embellishment and design. Though this does not mean that it is stronger or superior, it’s just better looking.

Forged Aluminum Lowers

On the complete opposite side of the spectrum, forged aluminum lowers are created by hand. This process can often be referred to milled aluminum, because the lower is hand formed by hammering the metal into place.

Forged aluminum parts tend to be much stronger, and much more accurate once installed in your weapon. Though, they can be more expensive because they are not as easily created

Overlapping the metal, creates a grain, that has been proven to stand the test of time, stress tests, and combat tests. Typically most operators will agree that forged or milled aluminum is the superior option when concerning aluminum parts.


Now, as will all things, it all comes down to preference and personal opinion. Though across the board, most operators would agree that a forged aluminum lower will be best because it is stronger, more durable, and just overall better.

Yeah, it will cost you a couple extra bucks, but in the long run, you will save a lot of money. Cast parts tend to break easily, along with billet. So if you’re looking for the longevity of parts, and not how good it can look, forged is definitely your best bet.

Though on the other hand, if you’re not really too worried about your weapon being combat ready, and you just want something that looks cool, then billet is a fine option for that particular case.
There are a lot of options to consider, but make sure you take into account what you intend to do with your AR-15, this can play a very important role in helping you decide which type of aluminum will suit your purposes the best.


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