Last updated October 26, 2026.
Short answer: You can build an AR-15 online by picking every part yourself, or by starting from a complete rifle and adding to it. The lower receiver is the part federal law treats as the firearm, so it ships to a licensed dealer in your state. Everything else can ship to the dealer or to your house. Our AR-15 builder checks each part against the rest of your build before it goes in the cart.
We like building ARs because it’s about the closest thing to an adult Lego set that also goes bang. The hard part has never been the wrenching. It’s ordering a gas tube that doesn’t match your barrel and finding out when the box shows up. Here’s how to build one online without that kind of surprise.
Two ways to start
Start from a complete rifle or pistol
If you want an AR that shoots out of the box and you just want to dress it up, start with a complete rifle or pistol. Pick from our AR rifles or AR pistols, then the builder walks you through the add-ons: optic, mount, magnifier, muzzle device, trigger, grip, stock, handguard, charging handle, sling, light and magazines.
Start from a lower
If you want to choose every part, start with a lower. Pick a stripped or complete lower receiver, and the builder takes you through the lower parts kit, trigger, grip, buffer kit, stock, upper, barrel, gas block and gas tube, handguard, bolt carrier group, charging handle, muzzle device, optic, sling, light and magazines. This is also the only path where you can have us put it together.
If you’d rather not pick parts one at a time, we also carry AR-15 build kits.
The fit checks that matter
Most AR parts are standard. “Most” is the word that gets people. These are the matches the builder checks for you:
- Gas block to barrel. The gas block has to match the barrel’s gas journal diameter: .625″, .750″ or .936″.
- Gas tube to gas system length. The barrel sets the gas system length, and the gas tube has to match it. Drop-in handguards have to match it too. Free-float handguards come with their own barrel nut, so that check is for drop-ins.
- Bolt to cartridge. The bolt face has to match the cartridge the barrel is chambered for.
- Muzzle device to threads. The muzzle device has to match the barrel’s thread pitch and bore.
- Stock to buffer tube. The stock has to fit the buffer tube you picked.
Each part gets a label: Fits your build, Check fit, Fit not verified, or Doesn’t fit. A part that doesn’t fit has to be swapped before the build can go to the cart. “Fit not verified” means we don’t have the spec data to confirm it. It may fit fine, but check the product page specs yourself, and you’ll tick a box saying you understand before checkout.
How the parts ship
Federal law defines a “firearm” to include the frame or receiver of a weapon (18 U.S.C. § 921(a)(3)). On an AR-15 that’s the lower, the serialized part (ATF’s definition of frame or receiver is at 27 CFR 478.12). A dealer can’t ship a firearm straight to a buyer who lives in another state (18 U.S.C. § 922(a)(2), (b)(3)), so the lower always goes to a licensed dealer near you, where you fill out the Form 4473 and pass a background check.
When you build it yourself, you pick one of two shipping options:
- Ship everything to my FFL dealer. The lower and every other part go to the dealer you choose at checkout.
- Lower to my dealer, other parts to my home. The lower goes to the dealer, and the rest comes to your door so you can start on the upper while the paperwork gets done.
Call your dealer before you order. Make sure they take transfers and ask what they charge. Our how to buy a firearm online page walks through choosing a dealer, and our shipping policy has the details.
Let us assemble it
On a build started from a lower, you can choose “Send the full build to us for assembly.” Every part ships to our shop. For $100 we assemble it, mount the optic and function-check it, then ship the finished rifle to the FFL dealer you pick at checkout. If you’d rather have the fun of building it yourself, skip that option. You can also see the rest of our gunsmithing services.
State restrictions
Some states restrict AR-15s, certain receivers or features, or magazine sizes. When you pick your state in the builder, it’ll tell you if we can’t sell an AR build there and won’t add the build to your cart. Checkout blocks those states too. Even where we can ship, local rules on features and magazines vary, so read our State Shipping Restrictions before you order.
Please make sure you can legally own the finished build where you live. If you order something that isn’t legal to own in your state, the order is cancelled and refunded minus a 20% fee, per our return and refund policy. Nobody wants that, us included.
A note on short-barreled builds
A rifle with a barrel under 16 inches is a “short-barreled rifle” under federal law (18 U.S.C. § 921(a)(8)). Since October 9, 2026, ATF no longer requires NFA approval or registration for short-barreled rifles (ATF Open Letter; ATF update page). The Gun Control Act still applies, though. You still need to file a Form 20 before taking one across state lines (ATF FAQ 21). State law is its own animal. Maryland State Police say an SBR there still has to be federally registered (MSP Advisory LD-FRU-26-001), and Hawaii bans rifles with barrels under 16 inches outright (HRS § 134-8). The builder shows an info line when your parts add up to a short-barrel build. Short-barrel builds are blocked in restricted states.
This is general information, not legal advice. Check your state and local law, or ask an attorney.
Finish it out
Once the rifle’s sorted, the builder covers the gear too: red dots and scopes, weapon lights, slings and magazines. If you’re an Armory Club member and signed in, qualifying parts show your member price in the build total. If you’re not, the build summary shows what a member would pay for the same build.
Frequently asked questions
Can you build an AR-15 online?
Yes. You pick the parts online, and the lower receiver ships to a licensed FFL dealer in your state, where you fill out the Form 4473 and pass a background check. The rest of the parts can go to your dealer or to your house. Our AR-15 builder checks each part for fit as you go. Source: 18 U.S.C. § 922.
Should I start with a complete rifle or a lower?
Start with a complete rifle or pistol if you want a finished AR-15 and plan to add an optic, light, sling, magazines or upgrades. Start with a lower if you want to pick every part yourself, including the upper, barrel, gas block, gas tube, handguard and bolt carrier group. The lower path is also where you can have us assemble the build.
How does the AR-15 builder check compatibility?
Every part you add is checked against the parts already in your build. The builder compares the gas block to the barrel’s gas journal diameter, the gas tube to the gas system length, the bolt face to the barrel’s cartridge, the muzzle device to the thread pitch and bore, and the stock to the buffer tube. A part that conflicts is marked Doesn’t fit.
What does Fit not verified mean?
It means we don’t have the spec data to confirm that part fits the rest of your build. It may fit, but we haven’t been able to check it. Compare the specs on the product page before you buy. If your build has any unverified parts, you have to tick a box saying you understand before the build goes to your cart.
Can Canoe Creek Armory assemble my AR-15?
Yes, on builds you start from a lower. Choose to send the full build to us, and every part ships to our shop. For $100 we assemble it, mount the optic and function-check it. Then the finished build ships to the FFL dealer you pick at checkout. You can also skip assembly and build it yourself.
Why does the lower have to ship to an FFL?
Because federal law treats the receiver as the firearm, and the lower receiver is the serialized part on an AR-15. A dealer can’t ship a firearm straight to a buyer in another state, so it goes to a licensed dealer in your state. Ask your dealer about their transfer fee before you order. Sources: 18 U.S.C. § 921(a)(3), 18 U.S.C. § 922(a)(2).
Can I order an AR-15 build in my state?
Pick your state in the builder. If we can’t sell AR builds there, the builder tells you and won’t add the build to your cart, and checkout blocks those states too. Many states also limit certain receivers, features or magazine sizes, so read our State Shipping Restrictions page before you order.
Can I build a short-barreled AR-15?
Where your state allows it, yes. A rifle with a barrel under 16 inches is a short-barreled rifle under federal law. Since October 9, 2026, ATF doesn’t require NFA registration for one, but the Gun Control Act still applies, including a Form 20 before you cross state lines with it. Check your state law first. Sources: 18 U.S.C. § 921(a)(8), ATF Open Letter, ATF FAQ 21.
Start your build
Head over to the AR-15 builder and pick your starting point: a complete rifle or pistol, or a lower. If you’d rather browse first, start with our AR-15 parts.
