With the hard bits out of the way, I installed the trigger. This can take a bit of effort, but playing with the parts ahead of time to see how they fit together is a big help. Installing a Timney trigger is the easiest fix.

The handguard is tightened with the aid of an armorer's tool and a torque wrench.

I simply dropped in the Timney, installed the safety selector and the trigger pins, and then I tightened the two hex-head screws in the trigger assembly. The entire process took less than five minutes.

From there, all I had to do was install the trigger guard, buffer tube, buffer spring, buffer, stock, pistol grip, and various pins, springs and detents before moving on to the upper receiver.

The Upper Receiver
I must confess that DPMS made a mistake on my upper. I ordered parts but received a complete upper instead. I would have thought of it as a gift had the subject of this piece not been assembling my own AR. So, I disassembled the whole damned thing and laid out all the parts so I could put them back together.

My Brownells action block was a big help in assembling the upper. After tightening it down in the vice, I applied some antiseize lubricant to the barrel extension and tapped the barrel in to the index point.

Before heading to the shooting range to test-fire the AR the author built, he put the finished rifle through a thorough inspection and installed a Leupold 3.5-10X LR/T scope.

Next, I applied lubricant to the receiver threads and tightened the handguard. The manual says to torque the handguard to 30 ft-lbs, but you may have to tighten it a little more or less to align the gas-tube holes.

Once the barrel and handguard were installed, the gas block was a cinch. First, I slid the gas tube in and out a few times to make sure it was not binding in the gas-tube holes in the receiver or the handguard. When I saw that was problem-free, I installed the gas block and tightened the setscrews securely. After function-testing everything, I tightened the gas block's set screws with Loctite.

With its black finish and stainless, 24-inch bull barrel, the finished rifle is a good-looking piece. Fit and finish were excellent (save for a few builder-added "beauty marks"), and the Timney trigger provided a crisp, clean trigger that broke religiously at a hair under 3 pounds. I was anxious to shoot it, but I had to do a basic inspection before I could safely fire my new rifle.

The author fired this 1.46-inch group at 200 yards; it's darn good given the unbearable heat and gusting wind.

Pre-Shooting Inspection
I started out by checking to make sure everything was tight and that the controls functioned as they should. I tested the safety, the trigger pull, and the forward assist. I also checked to make sure the charging handle didn't bind and that the bolt worked smoothly.

The bolt and bolt carrier also required a close examination. I checked the carrier to make sure it was nice and tight, and that its screws were securely staked. I checked the extractor hook for damage and correct tension by inserting a cartridge case in the boltface (with the bolt out of the gun, of course), and then I checked for firing-pin protrusion. I also checked the headspace with go/no-go gauges.

You should always check the headspace before shooting a rifle you have assembled. However, for this project, since the upper originally came assembled, I knew the headspace had already been checked at the factory, so I did not perform this step.

When everything checked out, I cleaned and lubricated the rifle in preparation for test-firing.