AssembleAR is a free online AR-15 builder. You choose each component of your rifle — upper receiver, lower receiver, barrel, bolt carrier group, handguard, trigger, muzzle device, stock, optic, and more — and the platform checks that your parts actually work together as you go. Think of it as a build planner that catches compatibility problems before you buy, then shows you where to get each part at the best price.
When your build is done, you can save it to your account and share it with a single link — for feedback on a forum, to send to a friend, or to hand off to a gunsmith. There is no cost to use the builder and no account required to start.
For builders
As you add parts, our compatibility engine flags caliber mismatches, gas system length conflicts, handguard and barrel fit, buffer weight issues, and SBR considerations — before you spend a dollar.
See prices for the same part from multiple retailers side by side, then click through to buy directly from the source. No markup, no middleman.
From complete uppers and lowers to barrels, bolt carrier groups, handguards, triggers, muzzle devices, optics, and individual small parts — every category needed for a full build.
Always know which core components you still need before your build is complete. No more discovering a missing part halfway through assembly.
Every saved build gets a unique URL. Share your setup on forums, with friends, or with your gunsmith — anyone can open it and see the full parts list and price.
Start building instantly. Create a free account only when you want to save builds and come back to them later.
Browse 31+ part categories and select the components you want. Filter by caliber, brand, and spec.
The engine flags conflicts between your parts automatically — caliber, gas length, fit, and more.
Save your build and get a shareable link, with a full parts list and running price total.
For retailers
The AssembleAR partner program lets firearms retailers embed the same interactive builder on their own website — pre-loaded with their products and prices. Customers plan a complete, compatible rifle and buy every part directly from you, which raises average order value and cuts returns from mismatched components.
Import your products via CSV or product feed and map them to part categories. Your inventory shows up in the builder with your prices and your buy links.
Copy a single snippet and paste it anywhere on your site. The builder runs on your domain, pre-loaded with your products. Works with any platform.
Shoppers assembling a full build buy multiple parts at once. The compatibility engine reduces returns from mismatched components and keeps customers on your site.
Update products, prices, and categories from a partner dashboard. Bulk category assignment and import auto-detection make onboarding a large catalog fast.