AR15 Complete Uppers & Upper Receivers, Built to Order

Why Choose AR15Parts.com?

A complete upper is only as good as the assembly behind it, and a mismatched or unchecked upper is a wasted purchase no matter how strong the parts list looks. Our team assembles every upper in-house at our Denison, TX facility and stocks barrels from vetted manufacturers so each build matches its intended use. Here is what builders gain when ordering through us:

• Premium Barrel Selection: Wilson Combat, Ballistic Advantage, Satern, Faxon, and Shaw barrels are all stocked, letting you match profile, length, and material to your application.
• In-House Assembly and Headspace Verification: Every upper is assembled, headspaced, and function-checked before it ships, eliminating the most common failure points on factory-built uppers.
• Configurable Build Options: Barrel length, gas system, handguard, muzzle device, BCG, and charging handle are all selectable, so the finished upper reflects how the rifle will actually be used.
• Fast Fulfillment: Most custom-configured orders ship within 3-5 business days, with free shipping on orders of $99 or more.

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Uppers Built for Every Mission

The AR platform's versatility is exactly why builders choose a caliber-specific complete upper instead of settling for a factory rifle. Whether you are assembling a lightweight home-defense carbine, a suppressed hunting rig, or a match-grade precision upper, the components have to match the job. Here are the most common applications our customers configure uppers around:

• Home and property defense carbines in 5.56 NATO and 300 Blackout
• Suppressor-host builds with correctly threaded, gas-tuned barrels
• Big game and predator hunting across intermediate and full-size calibers
• Precision rifle competition and long-range target shooting
• Duty, patrol, and designated marksman configurations
• Truck guns, pack guns, and lightweight backcountry builds
• Range and training uppers for high-volume shooting
• Custom platform builds replacing tired or mismatched factory uppers

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Build Your Complete Upper Today

Choosing the right upper is not always obvious, and the people answering the phone at AR15Parts.com build these rifles for a living. Our team can walk through caliber selection, barrel profile, gas system pairing, and lower-receiver compatibility before you commit to a configuration. Every upper ships with a documented headspace verification and a function check.

Contact AR15Parts.com to start your build, or call (888) 706-0633 to speak with a builder directly. Our specialists answer questions on caliber, barrel selection, twist rate, and gas system tuning before you place the order.

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Frequently Asked Questions

Can I choose the barrel length, gas system, and other components?

Yes. Every upper is configurable: barrel length, profile, gas system, handguard, muzzle device, BCG, and charging handle are all selectable so the finished upper matches your intended use. Our specialists can recommend pairings if you tell them how the rifle will be run.

How long until my custom upper ships?

Most custom-configured uppers ship within 3-5 business days, because components are stocked at our Denison, TX facility rather than ordered after the fact. Specialty barrel selections may add time depending on current stock, which our team confirms before processing.

What should I look for in an AR-15 upper?

Focus on the parts that drive reliability and accuracy: barrel material and profile (4150 CMV or 416R stainless), a twist rate matched to your bullet weight (1:7 or 1:8 handles most 5.56 loads), a gas system length correctly sized to the barrel, and a quality bolt carrier group that's been MPI- and HPT-tested. If it's sold as a complete upper, confirm it's been headspaced and function-checked, and check that the handguard, muzzle device, and receiver finish are what you want. Buying from an assembler that headspaces in-house removes the most common failure points.

What's the difference between a complete upper and a stripped upper?

A stripped upper is just the bare upper receiver, no barrel, bolt carrier group, handguard, or charging handle, for builders who want to source and install every part themselves. A complete upper is fully assembled and ready to run: barrel, gas system, handguard, muzzle device, BCG, and charging handle installed, headspaced, and function-checked, so it drops straight onto your lower. The complete upper is the faster, lower-risk path; the stripped upper gives you full control over each component.

What is a barreled upper, and how is it different from a complete upper?

A barreled upper sits between the two: it includes the receiver, barrel, gas system, and usually the handguard, but ships without the bolt carrier group and charging handle. It suits builders who already own a BCG and charging handle and don't want to pay for duplicates. A complete upper includes those parts and is ready to fire once mated to a lower.

What barrel length and gas system should I choose for an AR-15 upper?

A 16-inch barrel with a mid-length gas system is the most versatile all-around choice for 5.56 NATO, balancing velocity, handling, and soft recoil. Shorter 10.5–11.5-inch barrels with a carbine-length gas system suit pistol and SBR builds for maneuverability, while 18–20-inch barrels with a rifle-length gas system favor precision and long-range work. Matching gas system length to barrel length is what keeps the rifle running reliably, which is why complete uppers pair them for you.

Why do headspacing and function-checking matter on a complete upper?

Headspacing verifies the barrel and bolt fit together within safe tolerances, it's a safety and reliability check, not an optional extra, and a poorly headspaced upper can cause malfunctions. Function-checking confirms the assembled upper cycles and feeds correctly before it leaves the shop. A headspaced, function-checked complete upper is the single biggest advantage over grabbing an unchecked upper off a shelf.