Complete AR Uppers in Popular Calibers

The intuitive design of the AR platform allows the user to change calibers and configurations effortlessly by unpinning the existing upper assembly and pinning on another compatible with the lower. Switching from .223/5.56 to .300 BLK is one common example, as these rounds are from the same parent cartridge and don’t even require a change of magazine. 

WMD Guns sells complete AR upper assemblies to make caliber switching easy. Since upper receivers aren’t serialized, we can ship these builds directly to your door. We even have complete uppers with BCGs and charging handles so you can be ready to go as soon as you open the box.

What Does a Complete Upper Assembly Include?

Our complete uppers truly have everything you need, including a charging handle and one of our premium bolt carrier groups. All the upper receiver parts come already installed, as do a handguard and muzzle device. Multiple handguard lengths and styles are available to suit your preferences.

Many of our complete AR uppers feature a nickel boron finish with our proprietary NiB-X® formula. This hard, slick coating protects the metal from heat, wear and corrosion for unbeatable reliability. Barrels are typically finished in rugged black nitride for an attractive two-tone aesthetic. 

We Stock AR-15 and AR-10 Complete Uppers

When switching between AR upper assemblies, there are some limitations. First, there’s no crossing between the AR-15 and the AR-10. The latter has a longer, larger action to accommodate bigger rounds, and an AR-10 upper won’t fit an AR-15 lower (or vice versa).

 Still, you can fit some impressively large rounds into an AR-15 pattern, such as the .350 Legend or .450 Bushmaster. If you’re buying a complete upper for your AR-10 lower, you’ll find options like the ever-popular 6.5 Creedmoor and classic .308 Win.

With our complete upper assemblies, you won’t have to worry about BCG compatibility. Just make sure you have a magazine for your cartridge of choice. 

Advantages of Having Multiple AR Uppers

With the many different AR accessories on the market, you can build a customized rifle, carbine or pistol for just about any application. Of course, you’re not going to want the same feature set for every purpose, which is where keeping several complete uppers on hand becomes the perfect solution. 

In the AR platform, your optic and accessories mount to the upper and therefore move with it. You can outfit a long-distance build with a scope, long barrel and bipod, then rig out a separate upper for plinking with a red dot and forward rest — and use both on one lower you know and love. 

When you use the same lower consistently, you become extremely comfortable with it and know exactly what to expect from the trigger, resulting in more consistent pulls and stronger shooting fundamentals. It’s an excellent way to get more out of your gun. 

Complete AR Uppers Ready to Ship

If you love the AR platform and are considering another caliber, buying a complete upper that includes your BCG and charging handle will make the change effortless. Best of all, there’s no need to involve an FFL, pay transfer fees and slog through paperwork. 

Explore our AR upper assemblies for sale to find what you’re looking for, or reach out to our team to discuss a custom design. We have plenty of options for barrels, stripped upper receivers, handguards and other components to finish out a complete upper for you.