Step-by-step guide to building your first AR-15. Parts selection, tools needed, upper and lower assembly, testing, and expert tips.
How to Build an AR-15 — Step by Step
Gather Parts and Tools: Acquire a stripped lower receiver, lower parts kit, buffer tube assembly, upper receiver, barrel, handguard, bolt carrier group, charging handle, and necessary tools including armorer's wrench, punch set, and vise block.
Assemble the Lower Receiver: Install the trigger group, safety selector, bolt catch, magazine release, and pistol grip into the stripped lower receiver using the lower parts kit.
Install the Buffer Tube Assembly: Thread the buffer tube into the lower receiver, install the buffer retainer and spring, then add the buffer and buffer spring.
Attach the Stock: Slide your chosen stock onto the buffer tube and secure it according to the manufacturer's instructions.
Assemble the Upper Receiver: Install the barrel into the upper receiver using a barrel nut, then attach the handguard, gas block, and gas tube.
Install the Bolt Carrier Group and Charging Handle: Insert the charging handle into the upper receiver, then slide the bolt carrier group into place behind it.
Mate Upper and Lower: Push the takedown and pivot pins to join the completed upper and lower receiver assemblies together.
Function Check and Test Fire: Perform a full function check of the safety, trigger, and bolt catch. Then safely test fire the rifle at a range to verify proper operation.
Frequently Asked Questions
Is it legal to build your own AR-15?
Yes. Federal law allows individuals to manufacture firearms for personal use without a license, as long as the firearm is legal in their state and they are legally allowed to possess firearms.
How much does it cost to build an AR-15?
A basic AR-15 build costs $400-$700 for parts. A quality build with a good barrel, trigger, and BCG runs $700-$1,200. Premium builds with high-end components can exceed $2,000.
What tools do I need to build an AR-15?
Essential tools include an armorer's wrench, roll pin punch set, pivot pin tool, vise block, torque wrench, and a sturdy workbench with a vise. Many AR-15 tool kits bundle these for $50-$100.