Published on July 6th, 2013 | by Nate Schultz (nsz85)29
How to Build an AR-15 Beginner’s Guide – Part One
You do not always have to go to a gun store to purchase an AR-15. Surprised? I know I was when I first ventured into the hobby of building custom AR-15’s. Some of you may not know, but building your own AR-15 is actually quite simple. However, if you do not know anything about the process, or where to start, you have come to the right place. I am going to start this “How to Build an AR-15″ series off with a list of frequently asked questions that I receive from individuals starting out with the hobby and possibly wanting to build their first AR-15.
Building an AR-15 FAQ
Q: Are there any rules or laws for building my own AR-15?
A: Only the same ones that apply to owning an AR-15 in your state.
Q: Do I need to register my AR-15?
A: There is no gun registry in the United States of America.
Q: Do I need to be licensed or be a gunsmith to build my own AR-15?
Q: How many AR-15’s can I build?
A: As many as you would like to build.
Q: If I build an AR-15 for myself, can I then sell it?
A: The same laws for private sales of firearms apply. Check your state laws.
Q: How do I buy a “stripped” or “blank” AR-15 lower receiver?
A: You will need to find a dealer that sells AR-15 lower receivers. Said dealer can be local to you, or online.
Q: Can I buy all the parts online and have them shipped to my home?
A: This is a long one, so get comfortable. Yes and no. All of the components for your AR-15 build can be shipped directly to you at your home except the lower receiver.
The AR-15 lower receiver is the only component that is considered the “gun”. Therefore, when purchasing a lower receiver for your AR-15 build, you will have to go through the same channels as when purchasing a firearm in your state.
For example, in my state of Minnesota, if I order a stripped AR-15 lower receiver online, I will have to provide the seller with a copy of an FFL (Federal Firearms License) and the address to said FFL. In other words, I just have to call my local gun shop and ask them to fax a copy of their FFL to the seller. The seller will then collect money from me for the receiver, and then ship it to my local gun shop. When the gun shop calls me to tell me that my lower receiver has arrived, I will go there and fill out the ATF form to make sure I can legally own a firearm, pay a transfer fee (this fee is usually less than $30), and take my new AR-15 lower receiver home.
If I decide not to order online, and I have a gun shop that stocks lower receivers, I can just go purchase it directly from that store, and fill out the necessary ATF form just as I would for purchasing a firearm.
Q: What parts make up an AR-15 that I would have to purchase to build one?
A: There are a variety of different types of AR-15 builds, so this list will not work for all builds. However, I put together a list of components for building a typical M-4 style AR-15 with a stripped lower receiver, and stripped upper receiver:
1. AR-15 lower receiver
2. AR-15 upper receiver
3. Lower receiver parts kit
4. Upper receiver parts kit
5. Lower receiver extension (aka: the buffer tube)
7. Buffer spring
8. Barrel (a carbine length gas system would be typical for this build)
9. Hand-guards (length will depend on what length gas system you chose on your barrel: carbine, mid-length, or rifle)
10. Bolt carrier group (carrier, bolt, firing pin, cam, extractor, ejector and spring)
11. Collapsible stock
12. At least one magazine
Q: What is the difference between a forged lower receiver and a billet lower receiver?
A: With a forged lower receiver, the metal is “smashed” into the desired form while it is red hot. This compresses the metal and makes it very strong.
Billet lower receivers are machined from a single block of metal and tend to have a more custom, aesthetically pleasing appearance to some. It also tends to have the trigger guard built in, meaning it is not removable. They also tend to cost considerably more than a forged lower.
Q: How do I know which lower receiver to purchase? What “brands” are good?
A: There are a tremendous amount of different lowers out on the market, but not every lower is made by the company that has its name on the lower. You would be surprised at how many lowers from different companies actually come from probably less than a dozen machine shops.
At present, this is the list of which manufacturers produce lowers for which companies:
Lewis Machine & Tool
- DS Arms
- Knights Armament
Continental Machine Tool
- Rock River Arms
- High Standard
- Century (New)
- Global Tactical
- Wilson Tactical
- Grenadier Precision
- Double Star
- Fulton Armory
- Spike’s Tactical
- Double Star
- Charles Daly
Mega Machine Shop
- Alexander Arms
- Century (Old)
- Sun Devil forged billet receivers
- Superior Arms
- Lauer (New)
- Aero Precision
Considering that almost all AR-15 lower receivers are made to a very specific tolerance based on military specifications (mil-spec); my advice is to choose whichever AR-15 lower receiver that has a roll-mark (or logo) that you think is “coolest” or is most appealing to you personally.
Q: Some barrels say they are chambered in 5.56 and some say they are chambered in .223. What is the difference?
A: Basically the rule is: A barrel in 5.56 can shoot both 5.56 and .223 ammunition. A barrel in .223 can only shoot .223 and not 5.56. For more information on the difference between these two rounds, check out this article by Destinee.
Q: What does barrel twist mean? 1:7 and 1:9? Ratio? What?
A: Confused? Yeah, this one is kind of technical but I will keep it simple. When choosing a barrel twist ratio, you will want to choose one that best matches the type of ammo you would normally be shooting. What the ratio means, taking 1:7 for example, is when the bullet travels down the barrel, it will make one complete spin (via the rifling) every seven inches.
This is one of the most debated topics when it comes to AR-15′s. Personally, I chose to go with 1:7 because then I have the option of shooting the heavy rounds. Because 55gr .223/5.56 is the most available, and the most often used weight shot, you would be fine with either 1:7 or 1:9. I have also been told by reputable sources in law enforcement that one should use 1:9 for plinking, and 1:7 for hunting and home defense.
To break it down, 1:7 will do just fine with shooting lighter and heavier rounds. 1:9 on the other hand with handle lighter rounds better, and will not do so well with anything heavy at long distances. (Fig. 1a)
Q: What does carbine, mid-length and rifle length mean when choosing a barrel?
A: It simply means where the gas port in the barrel is placed. It is also sometimes referred to as the “gas-system”. Carbine and mid-length gas systems tend to be on barrels of 16-18 inches and shorter, while barrels with a length of 20 inches and longer will have a rifle length gas system.
It is important to know what length gas system your barrel has because the gas tube you purchase will need to be of proper length. For example, you cannot fit a carbine length gas tube onto a barrel with a rifle length gas system. The gas tube will be too short.
Q: I am ready to build my AR-15 lower receiver but I do not know the steps. How do I do it?
A: Great question. In part two of this “How to Build an AR-15″ series, I will go over how to build your AR-15 lower receiver, what tools you will need, and hopefully provide some helpful tips. Stay tuned.