Which is The Best M4 Lower Receiver in 2021? [Essential]

Why Should You Get a Great Lower Receiver for Your M4?

Getting the right lower receiver when you’re building your own M4 is extremely crucial as it can affect the overall performance of your gun. This guide will show you some of the best M4 lower receivers that you can get your hands on so keep reading to find out more.

Before moving on to the list of best M4 lower receivers, we will be showing you the different types of lower receivers on the market and followed by a guide to identifying the factors that make a great lower receiver.

Types of Lower Receivers

There are a few types of lower receivers that you can get and each of them can affect how well your firearm works so it’s important that you learn their differences.

Forged Lower Receiver

Forged lower receivers are the most common type that you will find on the market. They are made through a heat-hammering process and results in a decently strong piece. Forged lower receivers are also offered at a reasonable price and they are usually similar to one another regardless of the manufacturer that made it.

Billet Lower Receiver

A billet lower receiver is made from an aluminum billet with great precision to ensure its quality. With such a time-consuming construction, you can expect a billet lower receiver to be more expensive than forged lower receivers. It may cost you more, but the customizability it offers will be the extra money.

Polymer Lower Receiver

Polymer lower receivers are made with hardened polymer resins through an injection molding process. Sometimes, additional materials are added while the resin hardens to give it better strength and durability. Polymer lower receivers are usually lighter than the metal ones and because the materials used are cheaper, polymer ones will usually be cheaper.

80% Lower Receiver

An 80% lower receiver doesn’t have to go through inspection because it is not considered as a firearm according to the NICS or FFL. Compared to other receivers, an 80% lower receiver requires lesser tools to install and if you want to build a rifle from scratch then this type of lower would be the best choice for you.

What Makes a Good Lower Receiver For Your M4?

When you want to choose a lower receiver for your M4, you might want to make sure that it meets these recommendations so you don’t waste your time and money. Here are some of the things that you should be aware of when you choose a lower receiver for your rifle.

Type

The first thing that you should think about before you buy a lower receiver is the type that you need. Different types of receiver affect overall durability differently so make sure you decide on the type before you buy.

Performance Aspects

The performance aspects of a lower receiver refer to things like tension screws or magwells. These can affect how well your rifle performs and its service life too. You should think about the specific designs that you want and from there, you can eliminate lower receivers that don’t possess those designs.

Material

No matter what material is used for the construction of the lower receiver, it should be durable and has the weight that you prefer. However, if you are planning to fire a great amount of rounds, then you should look for lower receivers made from heavier and more durable materials. It will make your rifle heavier but it will also last for a long time.

Quality

The quality control of a lower receiver is usually good if it’s from reputable manufacturers so you should try to look for lower receivers by trusted companies with a good customer base. If you prefer to know more, you can always look at reviews for better details.

What Is The Best M4 Lower Receiver in 2021?

Now that you have a better understanding of the types of receivers that are available, we can now move on to the 5 best M4 lower receivers that are available on the market. Use the knowledge that you gained and choose the best one for your M4 rifle.

1. Aero Precision Gen 2 Stripped

Specifications

• 7075 T6 aluminum
• Holes, inletting and pin locations cut to final dimensions
• Clearly stamped safe/fire switch position indicators
• 5.56mm NATO

Features

The first choice that we recommend is this Aero Precision Gen 2 Stripped Lower Receiver. This is a semi-auto lower receiver that is built with forged 7075 T6 aluminum to military specifications and because of that, you are guaranteed with great durability and standards.

In addition to its strong build, the Aero Precision Gen 2 Stripped Lower Receiver is also extremely versatile. This stripped lower receiver is an excellent base for the 5.56mm, 6.5mm, 6.8mm, 30 AAC Blackout and 9mm Luger.

You can also expect this Aero Precision Gen 2 Stripped Lower Receiver to be a great fit for your upper receiver thanks to the receiver tension adjustment screw at the back of it. With such a good fit, there won’t be any rattling when you fire your weapon and it can really enhance your shooting experience to a whole new level.

Besides its clean aesthetics, you will also find a clearly indicated fire selector so you don’t need to mark it yourself. On top of that, the Aero Precision Gen 2 Stripped Lower Receiver is exceptionally affordable considering the functions and reliability it offers. Hence, the reason that it’s one of the M4 lower receivers.

You will like this if:

You are looking for a lower receiver with excellent durability. The Aero Precision Gen 2 Stripped Lower Receiver is built with high-quality aluminum to ensure that it’s durable.

You fancy a lower receiver that is built to mil-spec. This piece is built to mil-spec so if you are building a mil-spec M4 rifle, then this is easily the best choice for you.

You are planning to shoot different calibers that are compatible with the M4 or AR-15. The Aero Precision Gen 2 is compatible with many calibers so it will definitely work well with calibers that are compatible with the M4 or AR-15.

You will dislike this if:

You prefer to have more customizability. One of the cons about this item is the lack of customizability and also a reason why you might not prefer this.

2. Anderson Manufacturing Stripped

Specifications

• 7075 T6 aluminum
• Mil-spec, hard anodized finish
• Drop-in installation
• 5.56mm NATO

Features

If you are searching for the best budget option, the Anderson Manufacturing Stripped Lower Receiver will be a perfect choice. This piece by Anderson Manufacturing is less expensive compared to other lower receivers that you can get, but it functions just as well.

Just like the previous choice, this Anderson Manufacturing Stripped Lower Receiver is made from forged 7075 T6 aluminum. To improve its durability further, Anderson Manufacturing used a mil-spec hardcoat anodized finish for extra corrosion resistance. With such a build, you can expect this to last for a long time.

Due to the affordable nature of this Anderson Manufacturing Stripped Lower Receiver, there are some features that it lacks. Even though it’s not anything major, some people will still prefer to have it.

The things that it lacks are the trigger guard and adjustment to tighten the connection with the upper receiver. However, despite the lack of tightening adjustments, there’s still minimal rattling when it’s fully assembled.

Another feature of the Anderson Manufacturing Stripped Lower Receiver is the drop-installation. It’s designed to be easy to install with this feature and as a shooter, you will definitely appreciate this feature because it can save you some time and money.

You will like this if:

You are looking for the best budget option. In comparison with other lower receivers of similar build, the Anderson Manufacturing Stripped Lower Receiver is less expensive and affordable for most shooters.

You prefer to have a durable lower receiver with a high-quality finish. This lower receiver is made with forged 7075 T6 aluminum and has a hardcoat anodized finish to give it a corrosion-resistant feature.

You fancy having a good fit with the upper. Despite the lack of adjustment, there is still little to no rattling between the connection with the upper.

You will dislike this if:

You prefer a lower receiver with a nicer design and aesthetics. This item is not designed to have nice looks so it does lack in the design and aesthetics aspect.

3. Brownells Lower Receiver

Specifications

• 7075 T6 aluminum
• Matte black hard anodized finish
• Front takedown lug profile
• Machined to mil-spec dimensions

Features

This lower receiver has an impressive construction method that produces a lightweight lower receiver. Their lower receivers begin with an aluminum build to ensure that the receiver has a lightweight frame and to mimic the style of standard military-style lower receivers. It’s also designed for standard 5.56mm rounds use.

Followed by the completion of the mold, it will be machined to mil-spec dimensions to match the receiver used by standard, issued M4 carbines. This military spec receiver tends to be more expensive than the other military spec lower receivers due to the specialized aluminum construction that ensures a more durable product.

If you are going for the standard military look for your M4 build, you will find the matte black finish to match very well. However, unlike one of the previous models, this receiver doesn’t have any engravings for your firing mode so you will need to add it on your own.

Even though this receiver costs more than many models that are sold, it will definitely be worth your money for the versatility and standards it offers. This receiver is able to work with several M4 builds, including Models 618, 629, 630, and others.

You will like this if:

You prefer a lightweight receiver. This receiver is built with aluminum to achieve a lightweight frame while maintaining its sturdiness.

You are looking for a receiver with great durability. Thanks to the unique aluminum build, this receiver is more durable than other lower receivers that are built with aluminum too.

You fancy a versatile lower receiver. This is something that can work very well with a number of M4 builds, it includes Models 618, 629, 630, and others as well so you should find this to be compatible with your M4 model.

You will dislike this if:

You have a strict budget. Due to how this receiver is built, it is offered at a higher price range so if you don’t plan to spend so much, then this might not be the best choice for you.

You prefer to have markings for the fire selector. A small thing that this item lacks is the markings for the firing mode and if you prefer to have this feature then this might not be the best option for you.

4. PSA AR-15 MOE EPT

Specifications

• 7075 T6 aluminum
• Type III, Class 2 hard anodized
• Magpul MOE Stock
• Magpul MOE Grip
• Staked M4 Lock Nut

Features

The PSA AR-15 MOE EPT Lower Receiver is an aluminum forged complete lower receiver that is built slightly different from the mil-spec lower receivers. This complete lower receiver is able to work well with various calibers depending on your upper receiver and the barrel that you install.

If you plan to start an M4 build, this complete lower receiver would be the best choice.

Thanks to the nickel finish that this complete lower receiver uses, it is smooth enough to fit into your upper with ease. You will also find this nickel finish coated on the hammer and trigger.

The smooth nickel finish on the trigger is unlike the standard military-spec trigger, it is significantly smoother and is a finish that many shooters will enjoy.

In addition to the smooth nickel finish, this complete lower receiver is extremely lightweight and durable due to its aluminum build.

Even though this is a great complete lower receiver, it is not exactly recommended for beginners because of how highly-priced it is. But if you do give it a try, this complete lower receiver will give you the best value for money.

Overall, this complete lower receiver is a great piece if you are an experienced shooter since it gives you room for personalization and customization. As for beginners, this might not be the best option to start with but you can still give it a shot because this complete lower receiver won’t disappoint.

You will like this if:

You want a complete lower receiver with a great standard. This complete lower is an aluminum forged lower that ensures good strength and will last for a long time.

You prefer to have a top of the line trigger. The trigger that this complete lower use is unlike any other military-spec trigger, it has a smoother and nicer finish that enhances the trigger.

You enjoy the versatility this complete lower offers. This complete lower is able to work well with many kinds of ammunition and its versatility is one of the reasons that shooters buy it.

You will dislike this if:

You are not willing to spend so much on a receiver. Prices of great items are usually higher and there are no exceptions for this complete lower so if it’s too much for you then this might not be the right pick for you.

5. Brownells BRN-4 Stripped

Specifications

• Machined from original HK416
• Selector markings
• Type III hard anodized
• 5.56mm NATO

Features

The BRN-4 Stripped Lower Receiver is made with an HK416 forging and machined with precision to look like AR-15 lowers. This stripped lower receiver is the ideal selection if you prefer to own a stripped lower receiver that is easy to customize. It can also be a good lower for M4 lovers that are trying a new style on their rifle.

Not only can you use this on AR-15s or HK416s, but you can also use parts that are made for these rifles, for example, the Surefire 60/100rd magazines. Parts like these will work great with this stripped lower receiver as long as they are not disallowed parts mentioned on the site.

This lower is almost identical to one of the stripped lowers that was mentioned. It has markings on the side to indicate the firing mode and it has the same style as the HK416 model which enhances the similarity of these two lower receivers.

This stripped lower receiver is finished with a top-grade, anti-corrosive finishing to further enhance its durability by shielding it from external damages.

For a top-grade receiver like this, you should expect it to cost you a fortune. It is undoubtedly one of the most expensive lower receivers that you can get but it also gives you the best value that will be worth the cost.

You will like this if:

You are a fan of AR-15s and HK416s. The BRN-4 Stripped Lower Receiver is made with an HK416 forging and also adopts the style of the AR-15 model so you will definitely fall for this if you’re a fan of both firearms.

You planned to get a stripped lower receiver with impressive durability. This stripped lower is finished with top of the line finishing to achieve great durability.

You planned to get something with ample room for customization. Unlike a complete lower, this stripped lower has plenty of room for you to add parts to it and customize it.

You will dislike this if:

You don’t intend to spend so much on a receiver. This is a very expensive selection and is not the right pick if you don’t intend to spend so much.

FAQ

What is the difference between an M4 and an AR-15?

The biggest difference between the M4 rifle and the AR-15 rifle is that the M4 can be selected between semi-automatic and fully automatic while the AR-15 is semi-automatic only. However, both are identical and sometimes referred to as the same weapon. For instance, Colt, a famous firearm manufacturer sells their semi-automatic AR-15 rifles as M4s.

What parts make up the complete lower receiver?

There are several important parts that make up a complete lower such as the trigger assembly, magazine catch, grip, stock and the lower receiver housing. As for a stripped lower receiver, it will come with just the housing and no other components. It is also a way to differentiate between a complete and stripped lower too.