Can Any AR-15 Upper Match With Any AR-15 Lower?

AR-15 Receiver Set

There are basically two different types of people. The first type doesn't really want to get their hands dirty. They might have a hobby, but they're not into the do-it-yourself thing. You know the kind of person that drives their vehicle just the way it came from the dealer. They wouldn't even think about redecorating their house. Additionally, they're just fine with shooting their gun exactly the way it came out of the box. When eventually a problem comes up, it gets turned over to a professional to fix. Then there are the rest of us.

For better or for worse, we just can't seem to leave anything alone. For us, out of the box or off the shelf is not good enough. We are going to change our cars, houses, guns and just about anything else in our lives to fit our personal tastes. Of course, that doesn't mean that we are tasteless. In fact, often it's quite the opposite. The monogram on my wallet, the custom cabinets in my kitchen, or my AR-15 that's just a bit different is far from tacky. That's what makes it mine. The fact that you're even thinking about customizing your AR-15 puts you safely in that class of people that want something different.

Why Some People Want to Mix Upper and Lower from Different Brands?

The AR-15 platform is uniquely suited to this kind of person. Its modular design, combined with wide availability of parts, and the fact that you don't have to be an engineer to do the work, gives you the opportunity to easily design a gun that fits your needs perfectly. Of course, if money is not a problem, then you can easily order a weapon custom made just like a custom house. However, unlike a house, that pretty much has to come together in a certain sequence your AR-15 does not.

There are usually tradeoffs when it comes to getting exactly what you want. In many cases, the money you save is traded for your time. A deal normally comes in three elements they are quality, speed, and cost. For instance, if you want high-quality, and you want it now then it won't come cheap. On the other hand, if you want to save some money and have some patience you can have what you want. This tradeoff rewards you in another way, with experience.

The AR-15 platform is not overly complicated. However, it does have its nuances. Once you have taken your weapon apart and understand just what makes it tick, you gain understanding. When you mix different brands of an AR upper and lower receiver you take the first step on a journey of discovery. On the one hand parts are parts, however, some parts seem to play better with others. But why would you even want to mix and match parts for your AR?

Bought Separately When They Were on Sale

Well, first of all, we will look at leisure and price. When you're trying to find matching AR-15 upper and lower receivers you must have a source. Here at Wing Tactical, we carry an excellent selection of AR upper receivers as well as a multitude of other weapons components. As you research and put together your shortlist of desirable AR-15 match upper and lower receivers you might notice that the prices do not always stay the same. Manufacturers, as well as, Wing Tactical regularly run discounts, sales, and closeouts. When you go this route, you have the leisure to shop for separate AR upper and lower receivers, getting them for the best price you can find.

Building a Custom Lower and Going to Buy A Complete Upper

While it is true that "building" an AR-15 isn't that hard, there is a learning curve and there are certain tools you will need that are likely not already lying around your workbench. Now, assembling a lower receiver is significantly easier than an upper receiver. The entire trigger group, safety lever, mag release, bolt catch can all be installed with little more than an Allen wrench or two, a pin punch, and some Locktite. However, the upper receiver is just a bit more involved.

Again, this isn't rocket science but there are tricks. Mistakes can range from embarrassing to disastrous. People in the first group will probably stop reading right here and opt to scroll back up and order a complete rifle, and that's okay. However, people in our second group of do-it-yourselfers will likely take this as a challenge. While putting together an upper receiver is a bit more entailed, with the proper tools, preparation, and patience it is certainly achievable.

Wing Tactical is an excellent source for the specialty tools you are going to need. Additionally, you will find forums and YouTube videos all over the Web for instruction. Just please do your diligent research, for some people really don't know what they're talking about. At any rate, not everyone operates with the same skill set or resources.

Many people opt for starting with a small project and working your way into the more complex, which is actually a smart move. You can cut your Gunsmithing teeth on your first custom lower and obtain a complete upper to kind of get the feel for it. The beauty of the AR-15 platform is that by changing the upper receiver you can change the caliber of your weapon. You can bet that if you get bitten by the building bug, you are going to wind up with quite a few combinations of AR-15 match upper and lower receivers in your stable.

Want a Particular Logo/Style on Upper or Lower

The next thing to consider is availability and your preference. Of course, there are AR-15 parts available by the trainload, but are they the ones that you want? For instance, you find the perfect lower from brand A, but they don't have an upper receiver without a forward assist. You're going for a sleek, ultra-light build and don't feel the need for a forward assist. In this case, you will either change your build or find the upper you want from another manufacturer. This could easily go the other way. You want a traditional look and you wouldn't have a rifle without a forward assist, but brand A doesn't offer one. Here again, you are going to get what you want from the company that offers it even if that means using two different brands.

Some manufacturers offer some pretty wicked lowers that have designs made into the mag well. What if they don't have the upper that fits your build or budget? Maybe you want a particular logo to appear on your rifle. You can find it, but that brand doesn't carry the other half of the receiver in the design you want. This is another reason to mix it up.

Dual Tone Receivers

Dual Tone

For some people, the color or tone of a rifle means a huge deal. Not when it comes to pretty accents but to the overall look. With the AR-15 you don't have to keep the same tone throughout the build. You will find that different manufacturers offer different color choices for an AR upper and lower to fit your personal taste.

Maybe this isn't something you have ever considered. However, one day you might see a rifle in a magazine or at the range and it's all done up two-toned and you say why not build one like that. Could be that you join a club or start one yourself where everyone has matching weapons. There's nothing wrong with that. One particular upper comes from one manufacturer and the lower from another. This is but one more reason that might cause a person to mix and match their AR upper and lower receivers.

Can Any AR-15 Upper Fit Any AR-15 Lower?

Now comes to the question of whether any AR-15 upper receiver will fit any AR-15 lower. The answer is almost. Bear in mind that the AR-15 has been around for nearly six decades. There is no telling how many different manufacturers have cranked out these guns, and there is no regulation to control them. Except for the one little term, that term is Mil-Spec, do remember this because it will be on the test. It stands for military specification, and it lays out the dimensions and tolerances that are acceptable for the particular item. Now, unless someone gave it to me, I wouldn't try parts from an unknown source. However, any part sourced from a respected manufacturer that is designated as Mil-Spec should physically go together. One well-known exception is with Colt rifles made before 1991 and after 2009. During this period Colt designed their guns to use smaller takedown and pivot pins. Keeping this exception in mind, feel free to source trusted parts and build away.

Will Mixing Upper and Lower Receiver from Different Brands Affect Accuracy?

There are some people who maintain that a gun is going to be less accurate if you do not use the same AR-15 match upper and lower receivers. This thought is patently untrue. If you bear with me for a moment, I will logically prove this out.

The primary function of a lower receiver is to house the fire control assembly, magazine, and to hold onto the upper. I know, there are other little pieces in it, but it really just gives you something to hang onto. It's in the upper receiver where all the magic, or physics, happen.

Accuracy is attained or lost within the interface of your BCG, barrel, and handguard. Additionally, the length and grade of the barrel are vitally important. Now, if you combine a high-end lower receiver with a bargain basement, scrub upper then you would have a point of degraded accuracy, but who would do that? No, combining upper and lower receivers of different brands will make no difference in accuracy whatsoever. On the other hand, the quality of your upper receiver certainly will.

Things to Consider Before Mixing Upper and Lower Receiver from Different Brands

Okay, we have established that for the most part, AR upper and lower receivers from different manufacturers will physically fit together without affecting accuracy. Now we come to finish, this could be no big deal or a deal breaker. Either way it goes depends entirely on your individual perception and tastes.

Anodizing Color Might Not Match

Anyone who has ever tried to match the color of paint in your house, or on your car, knows that there are about a million different shades of any one color. Black should be black, but when the two parts go side by side, even a slight difference is noticeable. Even something as small as pins, safety selectors, mag releases can have a small, but significant, color difference that will stand out. Then there comes the anodizing process.

Every manufacturer does not necessarily adhere to the same process when they anodize their aluminum parts. Therefore, when you source parts from different manufacturers the resulting colors may be just a bit different. If you happen to obsess over the slightest variance in color and contrast this might be an issue. However, even time can change the color of a particular manufacturers components. This is a reality check here. As technology improves and companies progress, so do their processes of anodizing parts. So, say you bought an upper from one manufacturer today and a lower from the same company next year they still may not exactly match in color because their procedures have changed. Ultimately, you will probably notice it more than anybody else, kind of like a teenager with a pimple on the way to the Prom.

The Style Might Not Match

Another consideration for your AR upper and lower receiver is the process by which it was made. You have two choices, either one that is forged or one that is machined from an aluminum billet. There are valid points to be made on both fronts as to strength, durability, and accuracy. The purpose here is not to advocate one over the other, simply to point out the viability of mixing an AR-15 match upper and lower receiver.

The primary thing that stands out between the two is the price. Unless you stumble onto a great bargain, the forged receiver is always going to be lower in price. This is not necessarily because it is an inferior part, but due to the process of manufacture. Forging a receiver takes less time to complete, and time saved is money saved.

However, here we go back to finish. A receiver that is machined from an aluminum billet, usually has a cleaner, prettier finish than one that has been forged. So, you can save a little and opt for a forged lower receiver, putting that savings toward a higher grade billet upper. You will probably be able to see a difference in the finish when the upper and lower are mated. But, like the teenager with a pimple is it going to matter to you.


There is an ongoing debate when it comes to the AR-15 as to how loose is too loose when it considering upper and lower fit. Remember, this platform is designed to be quickly and easily taken apart and modified. If your AR-15 isn't a bit loose when you build it, just shoot it and it will eventually get that way. If you want a rock solid, precision fit then forget all about an AR-15 and go buy a bolt- action. However, let's talk for a minute about our perception of loose and tight.

The AR-15 has an upper and lower receiver that is made from some form of aluminum. The takedown and pivot pins are usually going to be either steel or titanium. Considering the abuse of recoil and wear from breaking down your weapon for even normal cleaning, the fit will loosen. Is the movement measurable with a feeler gauge or with a ruler? Remember that the accuracy is developed in the upper and as long as the weapon is safe to fire then lock and load.

That being said, you will find that AR upper and lower receivers will vary in exact fit between different manufacturers. That doesn't mean that they won't fit. Only that you will run into some that are easier to put together than others. As long as the receivers are Mil-Spec, they should mate. After building a few, most people find a specific brand they favor. This doesn't mean you shouldn't try something new. There are shims commercially available to tighten the fit between the upper and lower if it really bugs you.


Putting together a working AR-15 from a pile of parts can be a one-time experience, a rewarding hobby, or even bloom into a business. For quite a few people it starts with the basic idea that I can take two different things and make one useful thing. Even if it doesn't wind up being all that you expected, there's not really a downside. If you get your parts from a trusted source and do them no harm, there is a huge secondary market that is hungry for your leftovers. Additionally, if you're not careful, you just might learn something.

The most important thing is to read, learn, ask questions, and always get your parts from a reliable, trusted source. You don't really want to order from the bottom of the food chain and wind up stuck with something that you don't want, or worse, will fail. You can confidently order your AR upper and lower from us here at Wing Tactical knowing that you will be taken care of both before and after your purchase. If you have any questions as to exactly which part will fit your needs just contact us. That means for an AR-15 match upper and lower or any other component you have in mind. You will connect to a knowledgeable representative, not someone simply reading sales copy in a cubicle. We will find out what you need, explain your options, and help you make the right choice. Of course, you will feel confident in your choice to partner with Wing Tactical due to our wide product selection, superior customer service, fast shipping, and our 30-day, no questions return policy. View our AR-15 uppers and lowers today!