A proper Hessian knows his metal music intimately. He understands the moving parts and how they fit together to form a functioning whole. Just as a Hessian understands his music, he will also understand his weapons. What better way to understand our weapons than to build one ourselves? AKs are rather easy to build, but require some more expensive specialized equipment. ARs are also quite easy to build, and because of their ingenious modular design, one can either build a complete AR or one can build half an AR for use with already extant other halves. Because building an AR lower is somewhat more complicated and requires some more expensive equipment, today we will focus on building your own AR upper. You will see from the crappy pictures, taken with my old flip phone, that one needs no specialized facilities to do any of this – I did it in my spare bedroom in about 45 minutes. Recommended listening while building: Immortal’s “Battles in the North.”
My latest project was a long time in the making. The build started with a government profile 14 inch barrel with a welded-on 2-inch A2-style flash hider (to fulfill the 16” barrel required by the NFA laws) and a flip-up front sight that I bought a few years ago. More recently I acquired a cheap, off-brand upper receiver with a flat-top weaver rail. I would advise going the economy route on upper receivers as they are all essentially the same and you end up paying for a name more than quality. Granted, you may have to do some work with to achieve proper mating with the lower receiver (it took me a good 30 minutes of caliper measurements and sanding to achieve this with a previous build) but ultimately brand loyalty is for peasants. I personally prefer upper receivers without the forward-assist, but as these have gone out of style and are difficult to find, I simply bought a plug and dispensed with the whole forward-assist assembly. Only in the past few months did I purchase the last few parts I needed for this build.
The first step is to put on the dust cover. Align the loops of the dust cover with the loops on the receiver, slide it halfway in from front to back, and then slide the spring onto the rod and twist it into position before sliding the rod fully into place. Once assembled, the cover should be held firmly open and flush against the receiver by the spring tension. If it is loose, you have the spring on the wrong way. You can see it in the closed position in the picture below. I rather regret buying this particular cover, as the etching looks cheesy as hell, although I must admit it looked much cooler in the store. At least I didn’t waste that $15 on Immolation’s latest release.
Next we put the delta ring onto the barrel. You ought to have a specialized pair of delta ring pliers for this, but in all reality needle-nose pliers work just fine. A vise is convenient to hold the barrel steady, but not necessary. In the picture below,we have, clockwise from upper left, the delta ring, the spring assembly, and the retainer with my red delta ring pliers above them and the chamber of the barrel visible at the bottom left. With the muzzle in the vise, or pointed away from you, slide the delta ring onto the chamber of the barrel with the sloped part pointing towards the muzzle, put the spring assembly on making sure to keep the holes for the gas tube in both the delta ring and spring assembly more or less aligned along the top of the barrel, and then use the pliers to open the delta ring retainer so it will fit around the chamber and ‘snap’ into place in the groove machined into the chamber. The delta ring should be held firmly in place by the retainer (make sure it is seated in the groove a full 360 degrees around the chamber) and you should be able to push the delta ring backwards towards the chamber about 2/5ths of an inch against the forward pressure of the spring. You can see the fully mounted delta ring assembly in the second picture below.
Now we are ready to attach the barrel to the receiver. This absolutely requires a vise, an AR armourer’s wrench, which every AR owner ought to acquire anyhow, and to a lesser degree also a jig to hold the receiver securely in a vise. Place the receiver in the jig and then secure it in your vise. Next, liberally apply anti-seize compound to the threads on the upper receiver. Too much is better than too little, as the next time you will be seeing this area is probably years down the road after you’ve fired a good 10,000 rounds through the barrel. All manner of dirt and moisture will insinuate themselves in here so a goodly amount of anti-seize compound is a very good idea. Next, slide the barrel into the upper receiver and hand-tighten the barrel nut on the receiver threads. Next take your armourer’s wrench and fit the knobs into the slots on the barrel nut and torque the barrel nut tightly. The USMC armourer’s field manual says regulation torque is from 30-80 foot-pounds. I don’t have a torque wrench device, so I just lifted a 50 pound weight beforehand to get a vague idea of how tight I wanted it. It is better to stay on the low end of the torque regulations for reasons we will shortly see. Below you can see the armourer’s wrench, tube of anti-seize compound, and vise set up and in the second picture I have torqued the barrel nut.
Time to insert the gas tube. You will need a roll-pin punch and hammer for this part. First you will have to look down the top of barrel to make sure that the holes in the delta ring and spring assembly are vertically aligned with the gas tube hole in the barrel. If they are not, use a punch or small screwdriver to rotate the holes into alignment. Next, make sure the teeth of the barrel nut are properly aligned with the aforementioned holes. Here is where the lower-end torque comes into play. Slowly tighten the barrel nut until the teeth are properly aligned. With the barrel/receiver section still in the vise make sure that the ported end of the gas tube , with the two lateral holes for the pin and the underside hole that will fit flush over the gas port in the barrel, is facing forward (towards the muzzle of the barrel). In the picture below you can make out the underside gas port on the top of the silver gas tube that is leaning against the barrel. You can also see the hitherto lowered front sight has now been raised in the second picture below. Slide the gas tube into the receiver hole, then slide the ported end forward into the front-sight base until the pin holes in the gas tube align with the pin holes in the sight base. With the gas tube thus aligned, remove the whole assembly from the vise, and placing the front sight base on a block of wood, hammer in the roll pin to secure the gas tube. It should look like the second picture when you are done. All the difficult work is now finished.
Now we can put on the grips/heat shields. I went the non-traditional route with these and instead of GI-type round guards, I got some nice Magpul (made in the great state of Wyoming) guards. Unless you are a particularly weak 4-year old girl, you should be able to put on the guards without any tools – with the back of the receiver against the ground, push the front of the guard into position in the slot on the front of the barrel, push the delta ring back, and snap the guards into place.
The last lap. Time to put in the bolt assembly and operating handle. I purchased a Bushmaster complete bolt assembly. Bolt assemblies are the part that takes the most abuse, so I went with Bushmaster because they are known for very high quality. Unless you want to save a couple of bucks, just buy a full bolt assembly rather than one where you need to attach the gas-key yourself. Apply a light coating of oil to the locking lugs and along the side of the bolt carrier. In the picture below you can see the locking lugs on the right side of the bolt assembly and the gas key on top. You can also see the ‘trough’ on the underside of the operating handle. Now, partially insert the operating handle into the slot on the rear of the receiver, fit the gas key into the trough, and pushing on the back of the bolt assembly, slide the whole thing forward until you can feel the lugs lock into place in the chamber. You now have a finished AR upper, mine with 100% American parts and labor, that is ready to be mated with a complete lower receiver of your choice. You can see below I have put mine on a lower with an old A1 style buttstock which makes for a nice, balanced, compact weapon. You can also see part of the 20-inch upper receiver that was my first AR build in the lower part of the second picture. An old aluminum GI mag with snap caps is inserted to make sure the whole system is working properly. Not shown in the picture is the red-dot optic I later mounted on the flat-top rail. In the future I plan to put on a nice Knights Armament A2 flip-up rear sight as a backup to the optic.
All that is left is the fun part: take your new upper out to the range and test for function and then zero in the sights. I prefer the 50-yard zero. As a ‘battle zero’ the 50-yard will guarantee that your rounds, due to the ballistic trajectory of the bullet, will hit any target engaged out to about 250 yards with only about (+)(-)2.5 inches of vertical offset. After zeroing, you can fully enjoy the versatile AR-15 platform with long range precision shooting, tactical drills, or some good old fashioned mag dumps.