If you haven’t yet discovered “Black Guns,” then it’s about time you did. The AR-15 in its various configurations is the ultimate kit gun and the answer to a hobby gunsmith’s dreams. These guns are easy to work on, and the market is flooded with more “bolt-on” goodies than you can imagine.
   I had been thinking about a new upper in .204 Ruger for my DPMS rifle. So, when MidwayUSA announced that it would be offering Shilen drop-in, match-grade barrels for the AR-15 and that I could get one in .204 Ruger, I logged on to www.midwayusa.com and started shopping.
   I found that picking the components was easy. The MidwayUSA website has an AR-15 schematic that shows all the parts. Simply click on a part, and every brand and configuration of that part pops up.
   Before I started work, I went back to the website and the AR-15 schematic. I clicked a link at the top, and downloaded and printed a file called “Build the Ultimate AR-15.” The step-by-step instructions with color photos made building my new upper a snap, even though it was my first time.
   After checking the parts list to ensure I had everything I needed, I started with the forward-assist assembly. The first step is to start the roll pin that holds this part in place into the receiver. After starting the pin, simply place the spring over the forward assist, orient the part, and insert it into the upper receiver. Then tap the pin into place to hold it.
   Next is the ejection-port cover (1). Install the small snap ring on the cover pin. Place the cover on the receiver, and start the pin, but do not push it all the way through. The spring must be pre-loaded by turning the long arm one-half turn. Then you need to hold the spring in place, maintaining the tension as the pin is inserted all the way through. It helps to have two people when doing this operation. Even at that, I let out a few harsh words before I finally got it all together on about the sixth or seventh try!
   Next, the bolt assembly is installed in the bolt carrier. Make sure that the bolt and barrel are matched to ensure proper headspace. Push the bolt into the bolt carrier, making sure the extractor is oriented on the left as you are looking at the bolt face. Drop the bolt cam pin through the hole in the top of the bolt carrier, and rotate it one-quarter turn. Now slide the firing pin into the bolt (2). Insert the firing-pin retaining pin through the bolt carrier with the head of the pin matching with the recess on the bolt carrier, so that the head of the pin is below flush when installed.
   The charging handle is easy to assemble (3). Start the retaining pin. Place the spring in the hole, insert the latch, and hold it under spring pressure so the holes are lined up, and tap the pin home. Install the charging handle into the receiver, and then install the bolt assembly so the bolt carrier key rides in the trough on the underside of the charging handle. Make sure they can move in the receiver without any dragging or binding. Then take them both out and set them aside.
   Support the upper receiver with the action block, which will prevent distortion of the receiver as you install the barrel. Then clamp the action in the action block tool, and clamp the action block in a bench-mounted vise.
   Clean the threads on the receiver with a stainless steel brush, and coat them with an anti-seize compound. Insert the barrel. Thread the outer receiver nut until it contacts the ejection port cover pin (4). Then unscrew it one full revolution, and stop with the gas tube holes aligned. Coat the inner barrel nut threads with anti-seize compound. (White lithium grease will also work.) Hold the outer receiver nut to keep the gas tube holes in alignment as you tighten the inner barrel-retainer nut hand tight. The manufacturer of my floating handguard tube actually recommends coating the receiver threads with LocTite No. 271, installing the outer receiver nut and leaving it overnight so it can hold it in place. However, MidwayUSA recommends using anti-seize grease on the threads and holding the part in place during the tightening process. This proved challenging, and I needed several tries to get it right, but the extra effort paid off, allowing parts to remove easily. Had I used the permanent style LocTite, separating the parts would have proven troublesome.
   Tighten the inner barrel-retainer nut using a takedown wrench designed for this job. The wrench is designed to be used with a torque wrench, and the proper technique is as follows: Torque to 35 ft.-lbs, then loosen. Torque again to 35 ft.-lbs., then loosen again. Torque past 35 ft.-lbs., until the gas tube holes are in alignment, but do not exceed 80 ft.-lbs. The secret is to turn the outer receiver nut back slightly, so that as the inner barrel-retainer nut is tightened, the outer receiver nut will turn into alignment as the torque is applied.
   Install the gas tube (5), then slide the gas block down the barrel. Insert the gas tube into the gas block. Make sure the end of the gas tube with the three holes is at the gas block. Install the gas-tube pin through the gas block and gas tube. Tighten the set screws on the gas block. Install the sling swivels in the handguard, and install the handguard on the upper assembly to complete the assembly of the new upper.
   To mount the upper on the rifle, push the rear retaining pin out of the lower receiver. Tilt the barrel down and push out the front retaining pin. Now install the new upper and reverse the process. I selected a flat-top receiver with a Picatinny rail, so it was easy to install a Kahles 4-12x50 mm KX scope using Warne rings.
It’s all a lot simpler than it sounds. In just a little more than an hour after we started, my son Nathan and I were at our backyard range shooting the new .204
Ruger rifle.

Although building a rifle from the ground up might sound daunting, AR-15-style rifles present the perfect platform for the hobbyist as there are a multitude of available aftermarket parts. Steps can include: installing an ejection-port cover (1.); bolt assembly (2.); charging handle assembly (3.); installing the barrel (4.); and gas tube installation (5.).