Are you looking to find the best .458 SOCOM uppers to complete the build of your AR? If so, you’ve got a real project ahead of you. There’s an abundance of parts available for the AR in popular calibers such as 5.56x45mm NATO, .308 Winchester, or 6.5 Creedmoor.

Finding the parts you need to build an AR in .458 SOCOM is going to be a bit more challenging. It’s still a niche round trying to find its place amongst the new ones coming out. 

But don’t let that intimidate you. If you’re a beginner or a casual firearm enthusiast, we’ve got everything you need to know before purchasing your first .458 SOCOM Upper receiver. If you’ve already got an idea of what you’re looking for feel free to skip to our buyer’s guide or head to the Best .458 upper receivers.

	Cross Machine Tool INC AR15 CMT Billet Upper Receiver .458 SOCOM	Thickened receiver wall for added rigidity 5-axis machining process for a more accurate build Lightweight and durable Bilelt T6 7075 aluminum construction If you’re a beginner, you might need a professional to install	$211 Shop NowClick to read my review
	Anderson Manufacturing .458 SOCOM Upper Receiver	Great value stripped upper receiver Compatible with many Mil-Spec upper and lower AR-15 parts Matte black, Hard Coat Anodized finish Not for beginners	$73 Shop NowClick to read my review
Top Pick	Aero Precision AR15 XL Stripped Upper Receiver	Durable forged 7076-T6 aluminum construction Excellent AR-15 upper receiver for large ammunitions Smooth, corrosion resistant anodized finish May require prior AR builds experience	$95 Shop NowClick to read my review

The .458 SOCOM Cartridge

The .458 SOCOM is one of the more interesting and powerful rounds to come out of an AR-15. Even though the .458 SOCOM cartridge is almost twice as broad as the .223 or 5.56 cartridge, it can fire from an AR-15 lower receiver and load into the same magazines. It was developed as a very powerful and accurate, short to medium range round that provided a significant firepower increase for US soldiers.

The .458 SOCOM had to be easily loaded onto an existing M-16 Platform without making too many modifications. Thanks to its design, shooters could train with standard 5.56 ammunition and swap out upper receivers when necessary. Hence, saving money while providing flexibility to US Military personnel. However, in the US, this round has quickly found its footing as a hunting round.

This large .458 bullet, coupled with the sheer amount of energy behind its heavy 200-600 grain bullet, is enough for any game. It can sink anything from large elk, giant moose and even full-grown bears should the need arise. It’ll work great at stopping Wild Boar and larger bucks but you’re guaranteed to destroy the integrity of any animal less than 100lbs.

What is an Upper Receiver?

The upper receiver houses the barrel, forend, bolt carrier group, charging handle, and any AR attachments you choose to incorporate. You can also attach scopes and lighting. It links the lower receiver to the rifle, enabling you to modify the firearm’s look and functionality.

Why Upgrade Your AR-15 Upper Receiver?

When constructing for the 458, you’ll want to update your upper receiver and barrel, particularly because these rounds may weigh anywhere from 200 to 600 grains. An upper receiver upgrade eliminates the need to upgrade individual components like the barrel. However, make sure that they will function with your present upper receiver.

Parts of an Upper Receiver

Barrel

Because these bullets range from 200-600 grain, you’ll want to upgrade your upper receiver and barrel for the.458 SOCOM. You can reduce compatibility issues by updating the complete upper receiver rather than changing individual components such as the barrel.

Bolt Carrier Group

The AR-15 bolt carrier group (BCG) is the heart of your rifle. It is the primary component responsible for making your weapon function in the first place. The gas key, bolt, extractor, and firing pin are all part of this assembly.

They all work together to ensure that the gun is shot, the old cartridge is expelled, and fresh cartridges are removed from their magazine and inserted into the chamber. As a result, every shot completes and repeats the cycle. This is the mechanism that is responsible for the semi-automatic and automatic firing weapons on the market.

Charging Handle

The charging handle is the part of your BCG that initiates the first firing cycle. Imagine it like a car’s starter. The firing pin is “charged” when you draw the charging handle back to release a cartridge from the magazine. Then, it puts it in the chamber, and fires it. The charging handle stays still when the BCG rotates and only moves when you move it.

Forward Assist

As a relatively new AR-15 part, the forward assist is located on the upper receiver. Its major function is to help your bolt close all the way if it is unable to do so on its own.

Handguard and Rail System

The barrel of an AR-15 becomes very hot very rapidly when fired at a high rate of fire. Rail systems and handguards have been designed in order to preserve your hands from overheating while firing. You can also mount AR accessories like scopes, sights, flashlights, and lasers on rail systems.

Alternatively, handguards protect the barrel from heat and improve grip. When it comes to rail systems and handguards, you have a plethora of options in design, color, and style to pick from.

Ejection Port Cover

An ejection port cover’s primary function is to keep your weapon free of dirt and debris. When not in use, it serves to protect your bolt carrier group and upper receiver by covering the ejection port. When you press the start button, it will open by itself. Maintenance and upkeep, such as cleaning your AR-15 after shooting, are necessary to guarantee maximum performance.

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Uppers According to Construction

Uppers can come in a variety of materials. Although some lightweight uppers made from a mix of polymer and metal have started coming out, aluminum is still the preferred material of choice. However, beyond the type of material used, the type of construction process can also affect the cost and durability.

Forged Upper Receivers

Forged metal uppers give the optimal grain structure or orientation. It helps create the best balance of mechanical attributes including hardness, fatigue limit, specific weight, and others. But they are denser and heavier. To forge an upper, the upper is first hammered into the desired shape. This is done generally with the use of a mold, and then commonly finished up using a CNC lathe.

Billet Upper Receivers

To create the billet receiver, a CNC mill is used to cut a solid bar of metal into the desired shape. The mechanical qualities of billet metal are comparable to those of forged upper receivers. However, they’re usually less dense and lighter at the cost of losing some material strength. This is a trade-off you’ll have to think about when shooting heavy grain cartridges.

Cast Upper Receivers

In terms of strength-to-weight ratio, cast metal is the worst option. However, if you’re just looking for a lightweight upper receiver, then maybe a cast upper receiver will be good enough for your use. Cast uppers are created by die casting, a process where liquid molten metal is poured into a mold. Cast uppers usually come out rough and are finished off with a CNC Mill.

Flat-Top vs Carry Handle

You’ll also typically hear about ARs with A1, A2, A3, and A4 upper carry configurations. Although we can go into detail about the differences of each one, to keep things short, they either have a Flat-top or a carry handle on top of the rifle’s upper receiver.

A flat-top AR-10 upper is an AR-10 with standard Picatinny rail where the sights are usually mounted. In contrast, a carry handle upper will have a fixed carry handle on top of the upper which will act as the rear sight assembly for your firearm. While both of them exist out on the market, if you’re looking for real versatility, you should go with a flat top upper receiver since if you really want a carry handle, you can always add one to a Picatinny rail.

Buyer’s Guide for Upper Receivers

Types of Upper Receiver

First, think very carefully about the type of upper receiver that you’ll need for your build. The safest option, especially if you’re a beginner, will always be some variation of a complete upper receiver. Complete uppers are guaranteed to save you time and money and will work well for most scenarios. 

Also if you’re looking to shoot a lot of rounds out of your rifle, look for upper receivers that are forged or billeted. Forged and Billet constructions will give you upper receivers that are guaranteed to handle heavy grain cartridges better than cast upper receivers.

Build Quality

Investing in a high-quality upper receiver for your AR-15 is essential if you want your rifle to endure firing bullets for many years. For upper receivers, 7075 aluminum combined with a hard coat anodized finish is generally referred to as the gold standard. Aluminum is both sturdy and light, while anodized coatings are very rust and corrosion resistant, guaranteeing long-term endurance.

Although you’ll be able to find lightweight polymer upper receivers for your AR-15, I generally don’t recommend using these especially since most AR-15 rounds tend to be very large and use a lot of powder.

Heavier upper receivers will give you better stability and handle these more powerful rounds better than lighter materials, and polymer uppers will eventually give out from firing these large rounds. If you do insist on using polymer, look for ones with aluminum inserts at critical junction points to at least give you some better durability.

Manufacturer

Choose a receiver from a well-known, reliable brand with a loyal following of customers who are confident in the quality of their products. You can find out more about a product by reading reviews. With any firearm, you want to be confident with the parts you’re using. The last thing you want is your AR-15 falling apart during a self-defense scenario.

Also, by choosing one manufacturer, you’re almost guaranteed to have zero compatibility issues across the board since the same manufacturer will use the same specifications for their AR-15 build kits.

Best .458 SOCOM Uppers for 2022

Cross Machine Tool INC AR15 CMT Billet Upper Receiver .458 SOCOM

If you’re looking for a basic, no-frills, no-nonsense upper receiver, then it’s hard to look past the AR15 CMT Billet Upper from Cross Machine Tools, Co. This is a durable, stripped billet upper receiver that will get the job done at a reasonable price.

Cross Machine Tool Co., INC AR-15 CMT Billet Upper Receiver .458 SOCOM is constructed out of a lightweight yet durable T6 7075 aluminum with a hard coat anodized finish for superior rust and corrosion resistance. This makes it perfectly suitable for shooting in even the harshest conditions, a must for hunting and field operations.

In order to accommodate and withstand successive large rounds, these upper receivers come with an enlarged ejection port and a thicker than normal upper receiver wall for added rigidity. It’s completely compatible with other Mil-Spec AR-15 parts and will accept standard 5.56 bolt carrier groups and charging handles.

Since the AR15 CMT Billet Upper Receiver .458 SOCOM is a stripped upper receiver, expect to shell out some money on other upper part kits, like dust ports, forward assists, barrels, etc, if you don’t already have one. The upside is, theoretically, if you have a 5.56 or similar AR-15 configuration, you should only need to swap out to a .458 Upper receiver and barrel.

Anderson Manufacturing .458 SOCOM Upper Receiver

If you’re an expert gunsmith or have a lot of experience building AR-15s and are looking for a build challenge, then this upper might be the perfect starting point for you. This is a true stripped receiver that’s built to handle most of the larger-sized rounds on the market.

Anderson Manufacturing has several upper receivers in their line-up, and several of their receivers are designed to be ready to go with very little custom work needed. However, this is not one of them. If you’re committed to a custom .458 SOCOM build you need to be ready to put in the time and work with this upper receiver.

That being said, this stripped receiver is top-notch. It’s built out of 7075 T6 forged aluminum with a matte black, hard coat anodized finish to keep the sundown and make it even more rust and corrosion-resistant. The ejection port is enlarged to accommodate for the .458 SOCOM cartridge while the barrel extension comes with a larger relief to ensure reliable feeding.

This upper receiver is designed to fit any standard mil-spec AR-15 lower without any additional fitting and should work with most Mil-Spec AR-15 upper part kits. Although this would work with other large bullets like the 50 Beowulf or 450 Bushmaster, since it has purposely built feed ramps, it’s recommended you stick with just using the .458 SOCOM.

Aero Precision AR15 XL Stripped Upper Receiver

If you’re shopping around for an affordable yet solid upper receiver, then the Aero Precision  AR15 XL Stripped Upper Receiver is the product for you. Aero Precision is one of the most trusted Manufacturers on the AR-15 Platform, known for constantly producing reliable and high-quality products for a fraction of the cost. 

The AR15 XL Stripped Upper Receiver is one of the most popular products to come out from Aero Precision. It’s constructed from forged 7076-T6 Aluminum and matches to mil-spec M16/M4 Specifications. It’s finished off with a sleek anodized black coating for extra corrosion resistance. Durable and lightweight, it’s an excellent option for more experienced gun builders.

The AR15 XL Stripped Upper Receiver has an enlarged ejection port door opening and can accommodate the .458 SOCOM, 50 Beowulf, .450 Bushmaster, and other similar large rounds on the AR-15 platform. This upper receiver is compatible with a wide range of mil-spec AR-15 parts, however, it works best with the Aero Precision brand.

Our Pick

The Aero Precision AR15 XL Stripped Upper Receiver is an obvious choice if you’re shopping for an American-made product with superior quality and performance. This upper receiver assembly from Aero Precision is a high-quality, locally made, mil-spec upper receiver compatible with most AR-15 components.

How to Install Your Upper Receiver

Assembling an AR-10 and AR-15 upper receiver is very simple, and with the correct tools, you should be able to complete the entire process in as little as fifteen or twenty minutes, Just follow these steps:

1. Secure your upper receiver in a vice.
2. Place the barrel into the barrel opening; it should fit snugly.
3. Make sure that the alignment notch on the barrel fits into the groove on the upper
4. Thread on the barrel nut, and use a barrel nut tool to tighten it as much as you can. Make sure that the hole in the barrel nut aligns with the hole in the upper receiver to accommodate your gas tube.
5. Slip the gas block tube through the hole in the barrel nut; make sure that the block is aligned to the gas hole in the barrel.
6. Secure the gas block to the barrel with screws, and consider using Loctite for added security.
7. Fit the handguard over the barrel and thread it into the barrel nut.
8. Tighten the tension nut to help hold it in place.
9. Use a special AR tool for tightening up the handguard cap.
10. Thread on the flash suppressor.
11. Place the charging handle into the hole in the rear of the receiver where the bolt will go; make sure that it is aligned, which it will be if it slides into place.

By following these steps, you can get your upper receivers installed and ready to go for your AR-10 or AR-15.

Wrapping Up

Any one of the upper receivers that we have covered here is a solid choice for your .458 SOCOM. If you do decide to go a different route, you can follow the buyer’s guide section that we went over earlier to help you find a good upper receiver as well.

Furthermore, consider preplanning your build ahead of time. Finding out early on the type and classification of the upper receiver you choose will influence the outcome, the durability, and the cost of your AR-10 build. A complete upper receiver will almost always be cheaper than putting together a stripper upper receiver with upper part kits.

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