There's a debate going on in the small arms Community, and just about everyone you talk to has an opinion on this one: Which are better, forged or billet uppers? There are some pretty dedicated people on both sides of this discussion, but for the most part, it's a civil conversation. Of course, in the gun business we still settle our differences at the range occasionally, but at least this one hasn't become an issue worth taking to the battlefield yet. In most cases, choosing between forged and billet is going to rest on your personal preferences, so let's have a look at what each manufacturing method has to offer.
How Aluminum Uppers Are Made
There's no magic involved in making uppers. As we look at the two most popular kinds of uppers on the market you won't find a shining wand or pixie dust anywhere near. You might learn a little about metallurgy, but we'll get to that later.
Both Types of Uppers Are Machine-Finished
Let's understand these simple facts to begin with: Both types of uppers are made from the same basic materials, and they're both machine-finished. In the modern world, that means the blank aluminum billet or raw forged upper is loaded into CNC machining centers where it's shaped by tools turning thousands of revolutions per minute, guided by computers that have been programmed to do the work to create a part that matches a blueprint design. Whether it's forged or billet born, the final features of the receiver body are refined in the same way.
Billet Uppers Born From Barstock
Saying an upper is "billet" means simply that it's created from a single piece of stock. That "billet" is a piece of bar stock that was extruded to its raw dimension and cut to an approximate size. The billet upper will be machined from start to finish. This generally requires multiple steps or operations and might require a part to be loaded multiple times into different machines depending on the manufacturer's equipment and management plan. It takes longer to fully machine a billet upper than it takes to create an upper from a forged blank, but many believe that a fully machined upper is worth the extra investment and cost of that additional time.
Forging Is a Violent Process
Forged upper blanks are created by hammering the raw metal into a form that roughly resembles the desired receiver shape. The force of the repeated blows required to shape the metal to the form also has an effect on the composition of the metal itself. Metallurgists explain that the "grain" of the metal in forged pieces will be aligned. This creates a more uniform, stronger bond within the metal of the forged blank than exists in the raw materials of a billet upper. It takes less time to form a forged upper blank and complete the machine finishing than it does to machine a billet upper from start to finish. This makes it easier for manufacturers to offer forged uppers to consumers at an attractive price.
Dimensions, Strength, Accuracy and Compatibility
The greatest difference between one upper receiver and another for most shooters is going to be the physical features and aesthetics of the final product. Let's take a look at what we can expect from both kinds of uppers.
Forged Uppers Are the Standard
We already know that the forging process lends strength to uppers manufactured this way. That strength is important because strength and rigidity are what keep an upper within performance specs, making it not only safe but accurate. Because forging has become the industry standard for AR manufacturing, most manufacturers make their components with the dimensions of the average mil-spec forged upper in mind. It is rare to find an upgrade part that isn't compatible with a forged upper because there aren't many surprises in the dimensions.
Billet Uppers Are Unique
The manufacturers of billet uppers understand that their parts don't get the strength benefits that forged components do. In order to add extra strength and rigidity where it's needed, these fully machined uppers are designed with extra material around stress points. This adds weight to a standard billet upper and changes the outer dimensions of some so that they may have compatibility issues with parts that were created with mil-spec uppers in mind.
Precise Fitment: The Case for Billet Addressed
Billet enthusiasts often tout their uppers for having more precise fitment, but in practice, the fitment is only as good as the manufacturing of both parts in the marriage. Naturally, if an armorer marries a billet upper to a billet lower from the same manufacturer, it's going to be a match made in heaven. Mixing uppers and lowers from different manufacturers will still produce the occasional poor fit that occurs when trying to match incompatible forged uppers and lowers.
What Are You Reaching For?
It's important to remember that most manufacturers of billet uppers and the consumers who swear by them are reaching for a different pinnacle than those who prefer a forged upper. Forged upper enthusiasts like the compatibility, long-term strength and reliability of the stoic forged upper. It took many hits to create the forged upper, and it's ready to take plenty of other abuse during its service life.
Billet uppers often feature exclusive design modifications for lighter weight, proprietary and aesthetic qualities. Competition uppers are frequently billet uppers that have been redesigned for lower mass, creating a compromise between strength and weight. Those uppers wouldn't be used in builds intended for heavy use.
It's a Matter of Choice
In the long run, the choice between a billet upper and a forged one is largely personal to the shooter. Precision CNC machine finishing gives both types clean finished surfaces and creates parts that are true to print. Both types of uppers are equally strong, provided they are manufactured for the same intended purpose.
Choose the upper that fits your build, purpose and budget. Every shooter is unique, and every new build can be tailored to give the best shooting experience for the intended operator. Don't start with a compromise.