Build an AR-15 Gun

How to Build an AR-15 Gun?

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If you have been into the AR-15 platform, you have probably had an interest in building an AR-15 gun. There is much fun and learning when you engage in such projects. However, it requires you to have the right information, knowledge, parts, and tools to come out with a successful project of a functional AR-15.

This article is a brief AR-15 build guide. It outlines the necessary parts and tools needed and steps to follow while assembling your AR-15.

Build an AR-15
Build an AR-15 Gun

Build an AR-15 (Parts)

  • Lower receiver
  • Upper receiver
  • Stock
  • Pistol grip
  • Muzzle device
  • Lower parts kit
  • Buffer kit
  • Forward Assist
  • Gas block &Gas tube
  • Handguard
  • Bolt Carrier Group Assembly (BCG)
  • Charging handle
  • Barrel

Build an AR-15 (Tools)

  • Pin punches
  • Roll Pin Pusher
  • Utility Knife
  • Nylon/Brass hammer
  • A pair of pliers
  • Vise
  • Upper & Lower Vice blocks
  • Armorer’s wrench

One by one steps on how to build an AR-15

  • First, ensure you have all of the above-stated parts and tools. You must also have a clean table or surface with enough lighting where you will build your AR-15.
  • Start by installing the Forward Assist into the AR-15 upper receiver. Ensure the pawl faces straight into the hole in the receiver. Then compress the Forward Assist and drive the pin through its slot till it flushes with the receiver. You should use a roll pin punch.
  • In case you bought your BCG in individual parts, assembling it should be your next step. It also applies to the charging handle.
  • The next step will entail fixing your barrel assembly into the upper. However, you will have to mount the upper on the Vise and utilize the vise block. Thread the barrel into its place on the front part of the upper receiver. You shouldn’t forget to ensure that the pin on the barrel aligns with the small space on the receiver.
  • Proceed and thread the receiver nut and barrel retainer nut. You may apply some anti-seize grease before you start the threading. Also, your Armorers wrench will play a part in tightening the nuts and the barrel.
  • At this stage, you should now install the Gas Tube & Gas Block. Start by installing Gas tube into its hole on the upper receiver via the barrel nut retainer nut. The end of the gas tube with three holes is the one that goes into the upper receiver. Then position the Gas block onto the barrel as you guide the Gas tube into its place. Finalize this stage by tightening the set screws on the Gas block.
  • Now install your AR-15 free-float handguard or preferred rail system. Ensure the screws holes on the handguard and those on the receiver properly align.
  • Then install the BCG and the charging handle into the upper receiver.
  • Your AR-15 upper receiver is now ready. Let’s proceed and assemble the lower receiver.
  • Start by installing your magazine catch assembly into the AR-15 lower receiver. Press the magazine release button into its position thread the magazine catch from the other side till it flushes into position.
  • Then install the trigger guard assembly into the lower. Start by attaching the trigger and ensure its roll pins are well lined-up.
  • Ensure you have all the parts of the Bolt catch assembly ready. Fix the spring into the plunger then into their slot. Then drive in the bolt catch and align it before squeezing the bolt catch pin using a pair of pliers.
  • Go ahead and fix the trigger assembly. First, ensure your trigger spring legs and the disconnector spring are well aligned before placing this assembly into the lower receiver. You must also further align this assembly with the pinhole on the receiver such that you can see through before driving in the trigger pin. Your hammer and spring should come on top of the trigger. Then align them before pushing in the second trigger pin using your brass/nylon hammer.
  • Proceed and install your pistol grip on the lower side of the receiver. It’s also installed together with the safety selector. Properly align the grip with the lower receiver and screw in a nut to tighten them together.
  • It’s time to fix the rear takedown pin and a detent on the lower receiver’s rear part
  • Then position the buffer retainer and spring in place.
  • Screws in the castle nut on the buffer tube and followed by the end-plate. Then align this whole assemble of the receiver’s end and slightly screw the buffer tube on the receiver.
  • Ensure the end plate is in line with the spring before doing a further thread of buffer tube till it touches the buffer retainer. Ensure the spring is intact all time. Then continues screwing the castle nut.
  • Now install the front pivot pin and the detent its spring. The Utility knife is significant at this stage as it helps hold the detent spring while driving the detent itself.
  • Finalize this process by adding your buffer and buffer spring into its place.
  • At this stage, your AR-15 lower and upper receivers are complete. Now you should attach them, and you built an AR-15 gun.
  • Attach your loaded magazine and go for the function of your AR-15.

Best AR-15 Pistols


As you can see from the above procedure building an AR-15 is not a complicated process. However, you must be keen to assemble and every part appropriately to avoid any malfunction of your AR-15. Also, ensure you use quality AR-15 parts as you undertake your project. For more information, visit custom firearms.

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