The AR15's modularity has led to a boom in aftermarket customization options, allowing you to tweak everything from the stock to the muzzle brake. However, when it's time to pick between a billet receiver or a forged receiver, there always a tons of questions about it.
Before you dive into the sea of brands, styles, and prices for AR15 receivers, there's a fundamental choice you need to know. Let's break down the pros and cons of each.
Forged or Billet AR15 Receivers
The choice between billet and forged receivers for building an AR-15 often comes down to personal preferences, budget, and intended use.
Some builders prioritize the custom aesthetics and precision of billet, while others prefer the traditional look and inherent strength of forged receivers. Both types, when manufactured properly, can result in a high-quality and reliable AR-15.
Forged Receivers
The Strength of Forged Receivers
A standard forged AR15 lower starts as a block of high-grade aluminum. It's superheated and then hammered into the shape of a lower receiver. This forging process compresses the aluminum molecules, resulting in a remarkably strong component.
Forged lowers are typically lighter than their billet counterparts due to design differences and tolerances. They're also widely available and commonly sold. Many popular and no bs companies like BCM, Daniel Defense, Colt, FN...etc all mostly stick with forged receiver design.
Drawbacks of Forging
However, the forging process isn't without its downsides. The heat and pressure used in forging can displace aluminum, leading to imperfections that need to be removed. This can result in a less-than-perfect fit and finish, with potential gaps when paired with the upper receiver. Additionally, the forging process limits the possibilities for unique styles or designs.
Billet Receivers
Despite the higher cost, billet lowers are quite popular like the Radian A DAC receiver set. They offer excellent durability and quality, making them a cost-effective choice for many. The machining process allows for easy fabrication and design, resulting in a wide range of shapes and features.
Billet receivers are strong, but because they start from a solid block, their molecular grain structure is not as consistent as that of a forged receiver. This doesn't necessarily mean they are weak; they are still very durable.
The higher yield strength of alloys like 6061, which is heat-treated for maximum tensile strength, also contributes to their popularity.
Pros
On the other hand, a billet AR15 receivers look way better and feature complex cut patterns. It begins as a solid block of high-grade aluminum. A CNC machine mills this block into the final lower design. This process allows for extremely precise tolerances, often measured to a millionth of an inch.
When paired with a billet upper, you can expect a tight fit with no gaps, enhancing accuracy and reducing the chance of debris entering the rifle. Plus, the milling process allows for high customization, enabling you to create a truly unique build.
However, knock on wood, some receivers can still wobble, and this is where varying tolerance among receivers can still affect accuracy.
Drawbacks of Billet Receivers
While billet lowers aren't as "strong" as forged lowers, this is unlikely to be an issue unless you're pushing your rifle to extreme limits.
Billet lowers typically cost more than forged lowers due to the manufacturing process and the quality of the final product. The process starts with a billet block larger than the end product, which is then reduced in size through shaving and cutting. This results in a significant amount of wasted aluminum. The precision required in the machining process also demands more labor time, contributing to the higher cost.
Aluminum 7075-T6 vs. 6061-T6
When it comes to structural metal fabrication, aluminum is second only to steel in terms of attention. Aluminum 6061 and 7075 are the two most common grades used for structural applications. While they share many similarities, there are key differences to note.
The main difference lies in their chemical composition and alloy series, with 6061 having higher levels of zinc. Additionally, 7075-T6 has a higher tensile strength, nearly double that of 6061-T6.
| Aluminum Type | 6061 T6 | 7075 T6 |
|---|---|---|
| Ultimate Tensile Strength | 45000 PSI | 83000 PSI |
| Tensile Yield Strength | 40000 PSI | 73000 PSI |
| Shear Strength | 30000 PSI | 48000 PSI |
| Fatigue Strength | 14000 PSI | 23000 PSI |
| Hardness | 40 | 53.5 |
| Machinability | 50% | 70% |
Quick FAQ
Are billet lowers better?
Billet lowers are usually a bit heavier because of the extra material used for design or looks. But, the weight difference compared to forged ones is very small. Many people believe that the unique appearance of the billet justifies the slight increase in weight.
Are billet receivers compatible with mil-spec AR-15 parts?
Yes for the most of it. However, there are some proprietary designs that can negate the use of standard AR-15 accessories. For example, built in trigger guard makes any aftermarket trigger guard unnecessary to buy.