The AR-15 is one of the most popular recreational rifles for several reasons.
Number one: it is similar to those used by the United States military. Although the AR-15 does not have the fully automatic capabilities of the M-16 or the M-4, it looks close enough to the real deal to satisfy the desire for coolness among recreational shooters.
Number two: the AR-15 is extremely shooter-friendly. Recoil is very light when the firearm is chambered with 5.56×45 rounds. AR-15s are also very ergonomic compared to other rifles.
Number three: the AR-15 is extremely customizable, built with – as we’ll see in a minute -the same material used by the US Navy and Airforce for reinforcing modern warships.
The modular design of the rifle means you can swap out uppers and lowers within a few seconds.
You can change your AR-15 from a long-range sniper rifle to a close-quarters carbine just by changing uppers and lowers.
Table of Contents
How the AR-15 Came to Be
The AR-15 was first designed by a man named Eugene Stoner. Stoner developed the rifle as a lightweight alternative to the AR-10 while working at Armalite during the 1950s.
The lighter bullet used by the AR-15 enabled infantrymen to carry an increased number of rounds without adding to the weight of their gear. The AR-15 is the civilian semi-automatic version of the select fire M-4 rifle.
The lower is the “body” of the firearm, and is the only part that requires registration. You can have as many uppers as you wish without needing to fill out additional paperwork.
You can further customize the lower with aftermarket products to design the rifle according to your personal preferences and intended use.
But don’t get too carried away… There is a stigma (especially online) attached to those to load their rifles up with too much stuff.
These people are called “mall ninjas” and are accused of trying to be too “tacticool.”
Because the lower is where all the action takes place (no pun intended), it’s important that it be made well.
I hear your questions:
…Why are some AR-15 lower receivers $45 and others $200 or more?
…How do I know which one is best for me?
…Are the cheaper models poor quality?
…Are the more expensive versions less likely to develop problems in the future?
Don’t worry! It’s not as difficult as it may seem.
In this article, you will learn the differences in manufacturing, materials and weight to help you choose the best lower receiver for your budget.
In this article, I’ll touch on the following models of lowers:
- Aero Precision
- Battle Arms Development
- 2A Arms Balios
- Anderson Manufacturing
How They’re Made
Most lower receivers are made from aluminum. While there are other options such as steel, polymer and titanium, this article will focus on the three different ways aluminum is made into the receiver for an AR-15.
There are two types of aluminum alloys used in making lowers: 6061-T6 and 7075-T6. What’s the difference between the two? The answer is strength and resistance to corrosion. The figures are as follows:
The AR-15 started as the M16, back in the 1960s. When its designer, Eugene Stoner, conceived of the M16, he planned for the received to be built with 6061-T6.
This was all well and good – 6061 aluminum was plentiful, being used to weld rivets on Navy tankers and as chases for various Army vehicles. Yet around 1968, the military switched from 6061-T6 to 7075-T6 aluminum.
The switch from reliable 6061 to a different form of aluminum was expensive at the time, but necessary. Many of the M16s used in the Vietnam War were starting to corrode after exposure to the elements jungle warfare, and soldiers on the ground needed a solution.
Thus, Stoner recommended that the military switch to 7075 to fix the issue of corrosion (a common misconception is that it would make the receivers “stronger”, which was not necessarily true).
As evidenced by its widespread use in hangars and shipyards around the country, 6061-T6 aluminum is the superior option for welding and milling, and resists corrosion under normal conditions.
- Tensile strength: 45,000 psi
- Yield strength: 40,000 psi
- Shear strength: 31,000 psi
- Elongation: 17 percent
- Brinell hardness: 95
- Tensile strength: 83,000 psi
- Yield strength: 73,000 psi
- Shear strength: 48, 000 psi
- Elongation: 11 percent
- Brinell hardness: 150
7071-T6 aluminum is nearly twice as strong as 6061-T6 aluminum. As a result, there will be a difference between the two in cost.
Most AR-15 lowers on the market today use 6061 because it’s easier to mold, and quite hard. Further, most lightweight handguards for AR rifles are also made of 6061-T6.
6061 vs 7071 – Does it matter?
So why does 6061 take a lot of flak for being not as strong if it is so commonly used? Most of the hate comes from armchair elitist who will say stronger is always better and to never use lesser materials. When it comes down to the wire, stronger aluminum can’t hurt, but 6061 works, and has worked, for decades.
What does this mean for you?
Go ahead and buy that cool billet lower that is made of 6061 and be happy with it. Don’t worry about it breaking, despite what all the non-scientist elitist say. Just don’t take it to Vietnam.
When planning the build of your firearm, weigh the pros and cons of strength versus corrosion resistance to determine which type of metal you wish to use as your lower receiver.
If you cannot afford the more costly 7071-T6, 6061-T6 will be sufficient.
The casting process for aluminum is relatively basic. The molten aluminum is poured into a mold and allowed to cool. Once set, it is broken out of the mold, ready for the final machining process.
Because the aluminum is poured into the cast as a liquid, the final product will have a crystalline structure, making it the weakest form of aluminum product manufacturing.
However, it is still strong enough to withstand the pressure of firearm operation without risk of malfunction or damage.
With the billet manufacturing method, the lower starts its life as a solid block of pure aluminum. Over the course of the manufacturing process, it is machined and milled on a series of equipment modules.
Billet aluminum lowers are essentially sculpted just like stone or wood. Because these lowers are made from solid metal, they tend to be stronger than cast aluminum and have a better finish. If your gun is for show, consider a billet lower.
These lowers are also easier to customize than cast aluminum. Creative changes such as skull-shaped magazine wells and built-in trigger guards are simpler to create with raw metal.
This type of aluminum is the strongest form and is most commonly used for lower receiver manufacturing. The forging process basically consists of taking aluminum and forcing it into the desired shape.
The final machining process finishes the lower receiver. The compression caused by the forging process increases the strength of the aluminum.
Although the machining process is similar to that used to make a billet lower, the compression of forged aluminum creates a less refined appearance. Because of its extreme durability, forged aluminum is best for a heavy-duty AR-15 that you plan to use often.
Which Type of Lower Receiver Should You Choose?
Most websites will tell you that it is ultimately your decision and that you should consider the pros and cons carefully before making your decision.
We at Gun News Daily think it’s helpful to include some examples of high-quality lowers and talk you about them. Then you can make an informed decision about the lower you need.
We will not discuss cast lowers here for the following reasons: 1) They are weak. 2) They are ugly.
I’ve never used a cast receiver in any of my builds and would never recommend one to a fellow shooter. All that said, here are the top picks we’ve come up with.
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|Product||Rating||Price||Where To Buy|
|2A Arms Balios Lite||9.3||$$$|
We call this the Honda of lower receivers. Anderson lowers are inexpensive at $49 for stripped lowers and $120 for complete. They are made from forged 7071-T6 aluminum and are generally in stock.
I’ve used these lowers on countless builds and have never had any trouble with them. If this is your first time assembling a custom AR-15, I strongly suggest you choose this lower. If you scratch the metal during the assembly process, no big deal.
Don’t let the low price turn you away. These lowers are excellent as a basic lower for 90 percent of any build you design as a recreational shooter.
Like Anderson Manufacturing, Aero Precision lowers are forged 7075-T6 aluminum but with a fancier logo. You can pair the lower with an Aero stripped upper receiver for a streamlined appearance. Aero Precision’s lowers are a little pricier at around $90 at the lowest.
2A Arms Balios Lite
The Balios Lite comes on its own as a lower for $292 or as an upper/lower set for $499. This lower is my current favorite and will be on the next build I design.
It is one of the more expensive lowers, but it makes up for the cost with the wide number of build options compatible with it.
This receiver is even lighter than the B.A.D lower at 6.5 ounces. Some of my favorite features for this lower receiver include the contoured front for an ergonomic grip, an angled magazine well for faster reloads and the built-in trigger guard.
The reduced weight and the flared magazine will are perfect for the unique side-charger Go-Bag gun I intend to build with this lower.
The only drawback is its availability. The Balios Lite is difficult to find and is usually several weeks on back-order from the manufacturer.
One Last Piece of Advice
Admittedly, these lowers are only a sampling of those available. We selected these to give you a general idea of what high quality lowers look like. There are many other companies who manufacture and machine good lower receivers.
When you are evaluating lowers for purchase, be sure to take into consideration the material, the manufacturing process and the manufacturer’s reputation. Once you’ve decided on the manufacturer you wish to go with, you can check and see if your local gun shop has what you’re looking for to save on shipping costs.
One good way to determine the quality of a company’s lowers is to take a look at their rifles.
If the AR is well-made from the get go, the lower will be worth your time and money.
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