57 of 57 Items
57 of 57 Items
Your #1 source for all quality, mil-spec AR upper parts.
Piecing together a custom, precision-capable AR upper is one of the fun parts of becoming an AR-15 owner. We've got all the components you need to make that happen: From M4-type barrels to F/A bolt carriers, from lightweight handguards to oversized charge handles, you'll find everything you need to assemble any 5.56, .223, or other caliber upper assembly to pair with your new or existing lower.
Whatever you need to start or finish your AR's upper assembly, we've got it all: Lightweight, free-float handguards. M4-profile 4150 barrels. Gas tubes and low-profile gas blocks. M16-profile, .308, and 9mm bolt carrier groups. Charging handles. You name it, you need it, grab it here. All parts we sell for AR uppers are made in the USA and are forged, machined, and coated to mil-spec standards or better.
Two-piece handguards are cheap and effective, but they can hinder accuracy -- especially if you're rocking one of those old-school "FSB" front sight posts. It's time to upgrade to a proper, low-profile gas block and a quality, one-piece, free-float handguard. You'll shed some serious weight and free up your barrel from carrying the load, resulting in better accuracy.
Plus, you'll get to enjoy the M-LOK rail system, which also reduces weight and provides better ergonomics than the typical Picatinny quad rail. Each of our free-float guards are custom-made, sporting a hardcoat anodized finish and weighing one pound or less! Barrel nuts are included for an easy installation.
Want to make a true, one-off upper assembly that's designed and built to your exact specifications? Do it yourself, it's easier (and more affordable) than you think: We've got quality mil-spec, M4-type stripped upper receivers available, plus quality 4150 CMV barrels. Grab a BCG and charging handle, pair it up with one of those nice new handguards, and you're ready.
Follow our guide to install your AR-15 barrel, gas system, and handguard!
Virtually every AR barrel comes with standard 1/2x28 pitch or 5/8x24 pitch threads, so it only makes sense to finish (or upgrade) your AR's upper with a quality muzzle device that reduces felt recoil and improves control. Whether you're gunning for the traditional "bird cage" flash hider or you want to throw some flames and tighten up your groups with a proper brake or comp, we've got you covered.
Your custom AR upper awaits.
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 GunBuilders.com, 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.