The Black Rifle (Part Two)

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Thread: The Black Rifle (Part Two)

  1. #1

    The Black Rifle (Part Two)

    Well, thank God for the Internet. Everything you could ever need is at your fingertips. Including the instructions and parts to build your very own "ghost gun".

    While my project involved a rifle, this process is the same if you ever wanted to build your own semi-automatic pistol. You buy the unfinished, unserialized lower assembly and all the other parts, slap them together and BAM! Just in case you want a matching untraceable pistol. Plastics.

    The basis, the core of every modern firearm is the receiver. For an AR style rifle, this is specifically the lower receiver. All the other parts, directly or indirectly, attach to this part. As such, this is where I started.

    An 80% Lower must be machined-out to function. The bulk of this work involves removing material from the center of the partially-finished receiver, forming what is known as the "fire control pocket". In this cavity is where the trigger, hammer and safety selector switch reside.

    There are two main choices in material for a AR lower: Aluminum or Polymer. Aluminum is the default for all mass-produced AR rifles, as it is lightweight and durable. However, polymer is just as strong and easier to work with. So that was my choice.

    The lower kit I purchased came complete with drill bits, a drill guide and other small parts. The companyís on-line instructions highly recommend the use of a drill press for easier, uniform machining. Since Iím cheap, and chafe at instructions, I opted for my hand-held DeWalt.

    I took my time over a period of a few weeks. One of the drill bits was marked for the correct depth, but I also utilized a small ruler, marked appropriately. The amount of polymer removed was small in total, but the process is painstaking in that one must be very careful. If too much area is machined-out, you just canít put it back. Itís pretty messy, too. Graphite colored dust and long stringers of plastic bloom and have a tendency to go everywhere.

    I started the process in the garage, but it was Winter, and Iím not a total masochist. After mitigating the effects of mess, I donned my headlamp and old man reading glasses and got to work. For a while there, my wife was really getting sick of the sound of my drill grinding away. But she knew what she was getting into when she married me.

    Aside from the fire control pocket, the lower receiver also has other assorted pins and springs that must be installed. This was actually very easy. Stonerís design, over 60 years old, is nothing if not efficient. But everything must be assembled in a fairly rigid order. For example, the safety selector switch is held in place with a tiny pin and spring, which are in-turn held in place by the pistol grip. You canít install the safety without mounting the grip.

    The 80% lower does not come with all the small parts that make the rifle work. These parts can be purchased as a "lower parts kit" (LPK). As I progressed machining the receiver, I ordered a LPK.

    My first snag though was the fire control pocket. As I neared completely excavating the cavity, I kept test-fitting the trigger and hammer. The trigger would not reliably disengage the hammer. I was getting uncomfortably close to the outer wall and bottom of the cavity already. So I cheated, and ordered a "trigger module". This is a drop-in assembly that simply needs to be aligned with the holes in the lower receiver. Donít judge me. This was my first ghost gun. Iím learning.

    So, at this point Iím seeing the utility of using a more precise tool like a drill press. But no harm done thus far. And, the trigger module has the benefit of being more responsive than the standard Mil-Spec trigger. Although the drop-in trigger was pricey.

    I kinda got ahead of myself with the nuts ní bolts work (or pins and springs). I should explain the project goal. An AR style rifle has about as many variations as a mid-sized sedan. Except, you donít even have to follow Henry Fordís admonishment. You can build your "black" rifle in just about any color. Zombie Green is an option, as well as pink. But for the more serious minded, Olive Drab and Flat Dark Earth are popular.
    But I wanted to stick to "Mil-Spec" as much as possible. So it was black plastic for me. Yes, Iím boring. Sue me.
    Mil-Spec constructions are generally less expensive and more rugged. "Commercial" spec rifles are usually built for enthusiasts that like a lot of customization. Iím keeping it simple, and working within a budget.

    With the trigger module installed, and functioning properly, I added the butt stock and buffer tube to finish the lower receiver assembly. I chose a fixed stock as opposed to an adjustable one. The fixed stock adds weight and makes the rifle balanced and feel more stable. And, for aesthetics, I was looking at making the rifle look more "old school", like my 1980ís M16A2.

    So thatís pretty much the lower part of the rifle. Now, if youíre really hands-on, and a glutton for punishment, you can also assemble your upper receiver. And you better know what youíre doing here. This is where the bullet goes "boom". AR rifles use a simple but precise "gas assist" system to cycle each round. Mess up the gas system, you rifle is junk. And you can really screw up and have the upper blow-up in your face. Not really explode, just throw chunks of jagged metal everywhere.
    I bought a pre-assembled upper receiver.

    Again, there are no laws regulating the purchase of parts other than finished lower receivers. Even though the upper receiver is literally half of the rifle, you can just buy one and have it shipped to your door.

    The main things to look for in an upper receiver are barrel length and barrel twist. The minimum length for a rifle barrel is 16". You can find and purchase shorter barrels, but if you mount a short barrel on your rifle, you just committed a felony. Itís a stupid legal morass. If your weapon doesnít have a stock, then a short barrel is okay, because now technically itís a pistol. This is what happens when politicians and lawyers regulate stuff that they have no clue about. Just remember: 16 inches.

    Longer is okay, for sure. Longer barrels are more accurate and produce greater velocity. But Iíve shopped around, and trust me, you pay a premium for an extra few inches. And I am on a budget. Shame, too. The A2 profile is a 20" barrel. That would have added an extra $100 to the budget. Gotta fudge on that one.

    But, I was able to find a 16" barrel with a favorable rifle barrel twist. The rifling in a barrel spins the bullet, making it stable and accurate. The more "twisty", the better. Most commercial barrels twist once every 9 inches of length (1:9 twist). Some are better with a 1:8. I found an inexpensive, Mil-Spec upper with a 1:7. Score.

    Many, but not all "assembled uppers" come with a bolt carrier group. When shopping for an upper, you have to factor in that cost, as most BCGs are $80 to $100.
    Another thing that should be considered is how you will sight your rifle. Open "iron sights" are inexpensive and rugged. If you want an optical scope, it can get pricey. You must consider if you plan to use the scope exclusively, or be able to utilize your iron sights as a back-up. Almost every upper receiver assembly comes with a Picatinny rail to mount optics. Just something else to think about.

    Of course, it was iron sights for my rifle. I was a Marine, and we didnít use pansy stuff like scopes. And, did I mention, Iím a tightwad?

    When my upper receiver assembly arrived on my doorstep, it was the moment of truth.
    In theory, the upper and lower assemblies should just snap in place. Two pins join them. Thatís it.

    I placed them together and pushed on the pins. It was tight, almost too tight. I snapped them together. Itís kind of surreal. It is plastic, like a toy. But itís a deadly weapon.
    I held it out in front of me. It was a rifle.

    Oh, but this is far from over. Like I said, those pins were way too tight. They might need some sanding, or the holes need some slight reaming. I pulled the bolt back. It was stiff, but locked firmly in place. I released the catch, and the buffer spring forcefully slammed the bolt home. The metal-on-metal "click" was crisp and satisfying.

    All seemed well. But would my rifle actually work?
    There was only one way to know.

    "Now let's all agree, never to be creative again."

  2. #2
    Media Manager sigmadog's Avatar
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    You're making me want to build one myself! And I've even got a drill press!

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  4. #4
    Quote Originally Posted by Ralph Rotten View Post
    Well Ralph, I know your stated preference for the AK platform, but you have to admit one thing: The average person cannot forge or machine an AK receiver at home. With some drill bits.
    Additionally, if you are a fan of the 7.62x39 round, you can buy an AR upper and mags for that caliber. Best of both worlds (?)
    I'm covering that in Part Four. Wrapping up Part Three shortly.

    "Now let's all agree, never to be creative again."

  5. #5
    Actually, you can buy AK flats, fold 'em, spot weld the rails, and it's a receiver.
    They're as easy to make as an AR.

    Really, the only AR I'd be interested in is one of the convertable units that'll handle 243 or one of the other new 6mm wonder-rounds. I am a fan of 6mm projectile. Never had any use for 223 or 5.56.
    With my 243 I can use an 80gr bullet for varmints, or a 105gr projectile for deer and 2-legged snakes.

    That, and I'd only consider an AR if it was converted to a piston. The gas system makes an $900 AR less reliable than a $300 AK.

  6. #6


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