How to Disassemble/Reassemble an AR15

How to Disassemble and Reassemble an AR-15: A Step-by-Step Guide

The AR-15 is one of the most popular rifles in the world, prized for its modularity and ease of maintenance. Whether you’re cleaning, upgrading, or troubleshooting, knowing how to disassemble and reassemble your AR-15 is a must for any owner. At ArmsUnlimited.com, we provide top-quality AR-15 parts, tools, and accessories to make the process seamless. In this guide, we’ll walk you through each step with detailed instructions—and suggest where to find the best gear for your rifle.
Why Learn to Disassemble and Reassemble an AR-15?
 
Disassembling your AR-15 allows you to:
  • Clean critical components for reliable performance.
  • Replace or upgrade parts (stocks, barrels, triggers, etc.).
  • Diagnose issues like jams or malfunctions.
With tools and components from ArmsUnlimited.com, you’ll master this process in no time. Let’s get started.
Tools You’ll Need
 
Gather these basics (available at ArmsUnlimited.com):
  • AR-15 multi-tool or punch set
  • Cleaning mat or workbench
  • Gun oil or lubricant
  • Optional: armorers wrench (for advanced disassembly)
Safety First: Always ensure your AR-15 is unloaded. Remove the magazine, clear the chamber, and double-check before proceeding.
How to Disassemble an AR-15
 
Follow these steps to break down your AR-15 into its core components for cleaning or maintenance.
 
Step 1: Separate the Upper and Lower Receivers
  1. Push the rear takedown pin (near the stock) from left to right until it stops.
  2. Push the front pivot pin (near the barrel) from left to right.
  3. Pull the upper receiver upward and forward to separate it from the lower.
Image Placeholder:
Illustration: Side view of an AR-15 with arrows showing the rear takedown pin and front pivot pin being pushed out, upper receiver lifting off.
Step 2: Remove the Bolt Carrier Group (BCG) and Charging Handle
  1. Pull the charging handle rearward slightly.
  2. Slide the bolt carrier group out of the upper receiver.
  3. Remove the charging handle by pulling it back and lifting it out.
Image Placeholder:
Photo: Close-up of the upper receiver with the BCG and charging handle partially removed, arrows indicating motion.
Pro Tip: Shop replacement BCGs and charging handles at ArmsUnlimited.com for peak performance.
Step 3: Disassemble the Bolt Carrier Group
  1. Remove the firing pin retaining pin (small cotter pin on the side of the BCG).
  2. Slide the firing pin out of the bolt.
  3. Rotate the cam pin 90 degrees and pull it out.
  4. Remove the bolt from the carrier.
Image Placeholder:
Illustration: Exploded view of the BCG with labeled parts (firing pin, cam pin, bolt, carrier) and arrows showing removal order.
Step 4: Remove the Buffer and Buffer Spring
  1. Press the buffer retainer pin (inside the lower receiver, near the stock tube) with a punch.
  2. Pull the buffer and spring out of the buffer tube.
Image Placeholder:
Photo: Lower receiver with a punch pressing the buffer retainer, buffer and spring being extracted.
Step 5: Optional Advanced Disassembly
For deeper maintenance (e.g., barrel or stock swaps), use an armorer’s wrench from ArmsUnlimited.com to remove the barrel nut or castle nut. This requires more expertise—consult a gunsmith if unsure.
 
How to Reassemble an AR-15
 
Now, let’s put your AR-15 back together. Reverse the process with care.
 
Step 1: Reassemble the Bolt Carrier Group
  1. Insert the bolt into the carrier, aligning the gas key.
  2. Insert the cam pin and rotate it 90 degrees to lock.
  3. Slide the firing pin into the bolt.
  4. Secure it with the firing pin retaining pin.
Image Placeholder:
Illustration: BCG reassembly with arrows showing the bolt, cam pin, and firing pin being installed.
Step 2: Install the BCG and Charging Handle
  1. Place the charging handle into the upper receiver, aligning its tabs with the slots.
  2. Slide the bolt carrier group (bolt forward) into the upper receiver.
  3. Push both forward until the charging handle locks in place.
Image Placeholder:
Photo: Upper receiver with charging handle and BCG being inserted, hands guiding components.
Step 3: Reinstall the Buffer and Buffer Spring
  1. Insert the buffer spring into the buffer tube, followed by the buffer.
  2. Press the buffer in until the retainer pin snaps up to lock it.
Image Placeholder:
Photo: Buffer and spring being pushed into the buffer tube, retainer pin visible.
Step 4: Reattach the Upper and Lower Receivers
  1. Align the upper receiver’s front pivot point with the lower’s pin.
  2. Swing the receivers together.
  3. Push the front pivot pin and rear takedown pin back into place (right to left).
Image Placeholder:
Illustration: Upper and lower receivers being joined, arrows showing pins sliding in.
Step 5: Function Check
  1. Pull the charging handle to ensure the BCG moves freely.
  2. Test the trigger (dry fire, with no ammo) to confirm reset.
  3. Verify the safety selector works.
Bonus: Upgrade your trigger group with options from ArmsUnlimited.com for a smoother pull.
Tips for AR-15 Disassembly and Reassembly
  • Organization: Keep small parts (pins, springs) in a tray to avoid loss.
  • Lubrication: Apply gun oil to the BCG and buffer spring during reassembly—shop oils at ArmsUnlimited.com.
  • Manual: Refer to your AR-15’s manual for model-specific quirks.
Common Mistakes to Avoid
  1. Forcing Pins: Takedown pins should move smoothly—don’t hammer them.
  2. Misaligned BCG: Ensure the bolt is fully forward before reinstalling.
  3. Overlooking Wear: Inspect parts for damage and replace with quality components from ArmsUnlimited.com.
Shop AR-15 Parts and Tools at ArmsUnlimited.com
 
Ready to maintain or upgrade your AR-15? Visit ArmsUnlimited.com for:
  • Bolt carrier groups and charging handles
  • Armorer’s tools and punch sets
  • Replacement pins, springs, and buffers
Master your AR-15 with the best gear—shop now at ArmsUnlimited.com!