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36 of 51 Items
36 of 51 Items

 Pre-built uppers, custom barrels, upgraded handguards, muzzle devices and more.

Grab everything you need to build or upgrade your first or next AR-15 upper! We've worked closely with top makers like M-LOK, Aero Precision, GLOCK, and others to provide high-speed upgrades and OEM parts required to finishing or tricking out your custom AR rifle or pistol.

Precision-Built Uppers

All upper assemblies are assembled, torqued and function-tested to ensure your AR's ready to send rounds downrange once you tap down those pivot pins. Each upper assembly includes a mil-spec, M16-profile bolt carrier group and charging handle. All you need is your finished lower assembly! 

Assemble a custom upper with our how-to guide.

What Parts go in an AR-15 upper?

If you're building your assembly from scratch, your AR-type upper (and generally all upper assemblies, regardless of caliber) require the following upper parts. Our prebuilt upper assemblies include all components listed below:

  • Stripped Upper Receiver: The stripped upper houses the bolt carrier group and charging handle. It's also machined with threads and a small hole to attach the barrel and gas tube. 


  • Barrel: The barrel attaches to the receiver using a barrel nut. Most often, you'll use the barrel nut suppled with your handguard to attach both the guard and the barrel to the receiver. Most barrels are threaded for attaching a muzzle device, like a brake, compensator, or flash hider.


  • Handguard: Handguards are most often free-float, one-piece units machined from billet aluminum. They include attachment systems like Picatinny rails or M-LOK slots for installing accessories like a foregrip or flashflight.


  • Gas system: The gas system includes a gas block, pins to secure the block to the barrel, and a gas tube that feeds back into the upper receiver and bolt carrier.


  • Bolt carrier group with handle: The BCG includes the bolt, firing pin, and mechanisms for chambering, extracting, and feeding rounds from the lower receiver into the upper receiver and barrel. Our uppers typically include a BCG and charging handle, but it will be clearly noted where they are not included. Rest assured we source high-quality BCGs built to mil-spec standards.


  • Muzzle Device: Although not required, it pays to install a muzzle device on your barrel - especially since most are threaded. A muzzle device can help improve accuracy, reduce felt recoil, and redirect spent gas from the muzzle away from the shooter, reducing muzzle blast.

Easy Drop-in Upgrades

Even if you just bought or built your AR-15, there's plenty of opportunity to upgrade. Make reloads quicker and easy -- especially if you're running a glass optic -- by investing in an oversized charging handle. Want tighter shot groups with less recoil? It takes a few minutes to swap out and torque down a new compensator, like the popular Midwest Industries Muzzle Brake. Piecing together an upgraded mil-spec rifle? Check out our M4-profile barrels, forged from 4150 CMV.

DISCLAIMER: “GLOCK” is a federally registered trademark of GLOCK, Inc. and is one of many trademarks owned by GLOCK, Inc. and GLOCK Ges.m.b.H. Neither 80% Lowers, a/k/a Tactical Gear Heads, LLC nor this site are affiliated in any manner with, or otherwise endorsed by, GLOCK, Inc. or GLOCK Ges.m.b.H. The use of “GLOCK” on this page is merely to advertise the sale of GLOCK pistols, parts, or components. For additional genuine GLOCK, Inc. and GLOCK Ges.m.b.H products and parts visit

DISCLAIMER: If you are new to the world of DIY gun building, you likely have a lot of questions and rightfully so. It’s an area that has a lot of questions that, without the correct answers, could have some serious implications. At, we are by no means providing this content on our website to serve as legal advice or legal counsel. We encourage each and every builder to perform their own research around their respective State laws as well as educating themselves on the Federal laws. When performing your own research, please be sure that you are getting your information from a reliable source.

We are a national retailer of individual components and not all products depicted on this website are legal in every state. Shipping of various products found on this website are prohibited to some states (such as California, Connecticut, District of Columbia, Hawaii, New Jersey, New York, Rhode Island, and Washington). The information, pictures, text or products presented on this website are not a representation by us, and should not be understood by you, that any product or completed firearm is legal to assemble or own in your state of residence. We encourage each and every builder to perform their own research about the state and federal laws that apply to them. It is your responsibility to understand the law and we encourage you to consult with an attorney or your local ATF representative.