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Building Your First AR-15: The Road Less Traveled
Oftentimes, when people get into firearms, they buy off the rack. There is nothing wrong with this; some don’t want the responsibility of putting their rifle together due to fear of the unknown, or feeling like it may blow up in their face, both figuratively and literally.
I’ve been there.
But for those of you who like to tinker, building your first rifle may seem like the only way. It comes with many benefits, including cost savings, knowing how your rifle works, and how to replace parts should something break. Of course, it’s more time-consuming, but this is a rite of passage.
There are more parts than you may think that make up your AR-15. Source
Parts You’ll Need (Rifle)
From a parts perspective, below is what you’ll want to make sure you have ready to go. However, for your first build, I recommend starting with a complete upper. This allows you to pick the majority of your components still, but saves you some time and headache. For the majority of the article, we’ll assume you go with a complete upper.
- Lower Parts Kit
- Complete Upper (or stripped upper)
- Lower Receiver
- Barrel/Muzzle Device
- Gas Tube/Gas Block
- Handguard
- Bolt Carrier Group
- Charging Handle
- Buffer Tube
- Buffer Spring/Buffer
- Stock
- Dust Cover (if you buy a stripped upper
- Forward Assist (if you buy a stripped upper)
You can build your dream rifle with a little know-how. Source
Tools You’ll Need
Once you’ve acquired all of your rifle’s components, you’re going to want a select set of tools on hand. You can get away with not having a few of these, but if you want to make assembly much easier, you’ll want to have most of these.
- Work Bench (Surface)
- Vice
- Clamshell Upper Block
- Punch Set
- Nylon Mallet
- Armorers Wrench
- ½ Inch Torque Wrench
- Torque Screw Driver
- Armorers Bench Block Puck
- Upper Receiver Reaction Rod (Geissele works the best)
- Anti-Seize Lubricant
- Rocksett
Having a good workbench is a necessity. Source
Assemble Lower Receiver
This is where that lower parts kit comes in handy. With these, you have all the necessary parts to assemble your lower receiver, eliminating the need to worry about missing any components.
Don’t worry if it looks overwhelming; they will all come together. There are plenty of videos available to help you get it done right the first time.
I know, it looks like a lot, but after you’re done, it seems easy.
Start with your magazine release. You will see that one part is threaded, which you will slide your magazine release spring over, followed by the magazine release button. Push the button in all the way and thread it together by spinning the long end.
No tricks here, just a nice and easy part.
Now for the bolt catch. Take the smaller retaining pin, plunger, and spring from your kit. Take the retaining pin and insert it from the back into the top hole that sticks out. Insert the plunger and spring into the small slot, with the plunger facing outward.
Now take the actual button and line it up flush with the two knobs sticking out (hold with your thumb). Taking the nylon mallet, LIGHTLY tap it into place.
That bar is what holds your bolt catch release in place. Source
The front takedown pin is next, which is held in place by a detent spring that you will see a hole for in the front. Take your detent spring, put it in the hole, followed by your detent. Using an Allen key or specialty tool, hold them in place while you slip your front takedown lever in.
Now assemble your trigger, trigger spring, and disconnector spring. The disconnector spring will be placed in front of the two circles inside the trigger, with the wider part of the spring facing downward. Put your disconnector on as well. Place them in their designated positions and align the holes on the trigger and disconnector. Then slide the pin in, with the longer, smooth end inserted first.
For your hammer, take the spring and hammer and assemble them, making sure the squared part is on the bottom. Insert it with the hammer in the up position. Line it up with the holes and insert the pin.
This is how your trigger and hammer should look before installing. Source
Install your trigger guard with the spring-loaded part facing forward.
Place your hammer in the locked position so you can install the safety selector. Insert your safety selector into the lower receiver. With your rifle upside down, you will see a small hole next to where your pistol grip will go. That is where your detent goes.
DON’T FLIP YOUR RIFLE YET. Your pistol grip keeps it in place. Install your spring in the hole and keep your finger on it while you install the grip, making sure the spring slides into the hole where the detent is located. To make it easier, have the pistol grip screw and crush washer already on the allen key so you don’t have to use both hands.
The spring has to match up with the hole seen on top there. Source
To install your rear takedown pin, you must first secure your buffer tube in place. Put your castle nut on with the notches facing the rear and your end plate on. Take your detent and slide it into that back hole following the spring.
Now, take the spring out and start threading it onto the buffer without fully inserting it. Take your last spring and plunger and slide it into the hole where the retaining pin for the buffer spring goes. Push the plunger down and thread it on until the small notch sticking up matches the notch on the buffer tube, then release it.
It should look like this when you’re done. Source
Insert the spring for the rear takedown pin and push the endplate against it to secure it in place. Make sure you don’t kink the spring. Now that it’s in place, use a little blue Loctite on the threads and tighten the castle nut.
This is where that last spring goes. Careful not to kink it! Source
Use your armorers’ wrench and ½-inch torque wrench to torque it down to 40 foot-pounds.
You just built your first lower!
Feel better? It wasn’t that hard, right? Source
Mate Your Upper And Lower Receiver
This is when your rifle starts to come together. Now that your lower is assembled, you can finally mate it with your upper receiver and complete the rifle.
Well, aside from attachments, of course.
Using those takedown pins you installed earlier, push both of them out (without removing them, of course), and start from the front. Line up the holes, push in the front takedown pin. Now, lower the rifle and line up the holes with the rear takedown pin and push that in.
You just built your first rifle.
Now go get some ammo and train. Source
Choose Your Stock
This is all up to personal preference. How do you want your rifle to look? What are you going to be using it for?
Typically, the B5 SOPMOD stock or Magpul CTR is the way to go for most folks, but there are plenty out there. Do some research and see what suits you.
Conclusion
That’s all there is to it. Building an AR-15 is extremely easy, so long as you have the right equipment to get the job done, and don’t rush the process. Take your time, look on YouTube if you’re a visual learner, and ensure everything works before you start shooting.
And if worst comes to worst, your local armorer can help you out. I’m sure you can get it done, though. Once you get past the lower, you’re pretty much in the clear. Unless you build the upper yourself as well, but we’ll get to that later.
Be good and take care.
