Looking for gun advice when it comes to owning a AR 15? Whether you bought a stock AR 15 from your local firearm dealer, or you are planning to build one from the ground up, one thing you need to understand as a new gun owner is the AR 15 upper components.

It’s one of those gun parts that are often overlooked, as other sections of the gun get much more attention. But choosing a complete upper for your AR 15 is an important decision, and you should do your research before pulling the trigger and grabbing the first upper that you see.

So what exactly is a AR 15 upper, and why is it one of the most important gun accessories? Keep reading to learn how these work, and why they are important for both gun safety and optimal performance. 

AR 15 Upper vs Lower

Before discussing the ins and outs of uppers, otherwise known as upper receivers, you need to know what the AR lower is.

The lower section of your AR 15 is what you interact with as the shooter of the rifle. This is where the majority of moving parts are, including the action. Basically, it’s the part of the gun that you actually operate.

And it’s also the regulated section of the gun. The AR lower is where your serial number lives. This serialized section of the gun is used by the government to track sales of firearms. So in essence, the lower receiver is, for all intents and purposes, the firearm itself.

It can’t be operated by itself, however. That means that any other components needed to make the gun operate can be added at your discretion, including the upper receiver.

So what is the upper receiver on a AR 15?

What is a AR 15 Upper Receiver?

The AR 15 complete upper doesn’t get a ton of attention because it doesn’t require much human interaction. But it’s vital to the build and functionality of your gun.

While it doesn’t feature as many moving parts, it still contains moving pieces necessary for proper functionality. This is the section of the rifle where the barrel is attached to the main body.

It serves quite a few functions, usually all at the same time. When firing rounds, bullets are being shot out the front of the upper while the spent casings are popping out of the side of the upper. 

New cartridges are being fed into the upper from the bottom while the bolt is hitting the back of the upper. The gases emitted from each shot are mostly dealt with by the upper.

So even though most people don’t touch or use this section of the gun, this component is vital to the entire functionality of the rifle. It doesn’t cause any of these things to happen, but it facilitates all of it in a safe and effective way to allow for the continued use of the gun. 

Upper Material Choices

Since the bulk of AR 15 components are made of aluminum, which is both strong, light, and cheap, so too are most upper receivers made from aluminum.

Those looking for super niche uppers may consider one made of steel, hybrid metals, or even plastic for a super-light solution. Those looking for lightweight, high-end uppers can also opt for titanium for a much higher cost. 

Most people will have no problem matching the material of the rest of their rifle, choosing a moderately priced aluminum upper. Of course, you can keep the stock option, or upgrade to an aftermarket receiver. 

Stripped vs Complete Upper

Depending on your skills when it comes to modifying firearms, along with your patience and your budget, you might opt for either a stripped-down upper or a complete upper.

A stripped upper receiver is essentially the outer shell by itself. It doesn’t come with any of the internal components that make the upper work. The idea behind a stripped receiver is that you are building out the rifle yourself, and want to source each component individually.

If you are new to firearms, this process is an incredible learning opportunity. It gives you the chance to truly learn the ins and outs of your AR 15, and how firearms work in general. However, unless you have some serious DIY skills, assembling a rifle with a stripped upper isn’t always the best option.

Want to know the easy way to complete or modify your rifle? Purchase a AR 15 complete upper instead. Because these come with all the internal components, along with a barrel, it is the more expensive option.

But it saves you a lot of time and a lot of hassle, as it has everything you need to connect to the lower section of your rifle. You’ll still get your hands a little dirty by having to install it yourself. But you just bypass many of the smaller, more complicated tasks, such as dealing with sights, bolts, charging handles, and other necessary components.  

The Struggle of Building Your Own Upper

Those who prefer to assemble their own upper receivers often run into some issues pretty early on. It’s actually quite hard to mix and match components for a truly unique gun.

Because different companies make upper receivers and components, they can choose to make them how they want. As a result, companies will often utilize unique, proprietary designs in their components that only work with other components offered by the company.

The result? If you want to use one component from a designated company, you might have to source all of your components from the same company. This means that each company will make more of your money, rather than you buying one component from multiple different companies. 

Of course, with a little determination, a lot of time, and a lot of tinkering, you can eventually tweak your way to a complete receiver, made up of differing parts completely assembled by you. And while it may take a lot of time, you’ll be proud knowing that you have a one-of-a-kind upper.

For everyone else, however, just buying a completed upper by a single company is the easy route, and will improve performance without much effort. 

Topping the Upper

There are different styles of upper receivers that allow for different levels of customization and flexibility. The most common on today’s rifles is the flat top upper.

With a flat top, you can add Picatinny rails, which is what most users do. These allow for the easy addition of your main optics, followed by a backup sight.

Designing a Left Handed Gun

If you are left-handed, you are probably used to feeling like you’ve been left out. Most products are intended to be used by right-handed individuals. This is the same when it comes to firearms.

Very rarely can you pick a gun off the shelf and shoot it comfortably as a left-handed individual. So swapping out the upper with a lefty upper is probably in your best interest.

On a left-handed upper, instead of metal casings ejecting from the right side (hitting your body), they will instead eject from the left side of the gun so that they don’t hit you. They’ll also be more comfortable to hold and shoot, making the upgrade worth the money. 

The Benefit of Multiple Uppers

For certain types of guns, it makes sense to have different barrels for different use cases. For example, with a hunting shotgun, you may try chasing different types of animals with the same gun.

For turkey hunting, you’ll need to hit a small target, often 30 yards away. For this, you’ll want a longer barrel that limits your shot pattern.

But for dove hunting, you’ll want a shorter barrel that allows for a wider shot pattern, since you’ll be taking quicker shots at tiny, moving targets.

If you are sitting on a lot of money, it makes sense to have different hunting guns for different game species. But for the rest of us, it’s much cheaper to have one quality gun, and then just swap out the barrels depending on what’s in season.

The same is true for a AR 15. Different applications would benefit from different barrels. However, changing the barrel by itself on a AR 15 is more complicated than most people are willing to do with.

The easier solution is to have multiple uppers. Upper receivers as a whole are very quick and easy to swap out. All it takes is the removal of some pins and pulling out the bolt, replacing it with your other completed upper.

It does cost more money to have multiple completed uppers. But if you find yourself changing shooting applications frequently, it can save you a lot of time and hassle. 

Putting it All Together

Now that you know all about upper receivers for your AR 15, it’s time to get back to work. Are you building your own rifle from scratch? If so, will you opt for a stripped upper or a complete upper?

There’s no right or wrong approach, it just depends on your skills, knowledge, and patience to have to buy all the parts and assemble them yourself.

Alternatively, you can remove the stock upper receiver from your rifle and replace it with an advanced option for increased performance or a unique aesthetic.

Which will you choose?

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