Slide your firing pin through the bolt carrier and insert the retaining pin. You want the round end of your pin to reside in the largest side of your bolt carrier. Exact alignment can be difficult so be sure that the pin can slide freely before moving on to the next step.
If all goes well, you’ll be ready to move on to your charging handle. You’ll need a latch spring for this. What you want to do right off the bat is place your latch spring inside of the charging handle and start a roll pin at the top of the handle.
As you compress the charging handle latch, just line up your holes and insert the latch roll pin. Once it’s flush, you’re good to go.
BOLT CARRIER & CHARGING HANDLE
From here, you want to install the bolt carrier and charging handle into your upper. Sounds easy, right? Not exactly. This is where things get a touch more involved.
You’re gonna need to turn your upper upside down again and insert the charging handle assembly, carefully aligning the tabs on the handle with the grooves of your upper.
Slide the handle assembly just enough so that it’s inert, then pull your bolt out of the carrier to the point where the cam pin won’t touch the interior of your upper.
Now you’re going to insert the bolt carrier assembly into your charging handle assembly. You want both assemblies to be aligned, otherwise your unit will not be functional.
Push both assemblies into your upper so that they click into place.
At this point, you should be ready to insert your upper into the action block by tightening it with a vise. To do this, you need to remove your assemblies and slip your action block insert into the rear of your upper.
Shut your ejection port cover, put the upper into the block and shut the block. Then put the block into your vise and tighten without overtightening.
OUTER & INNER RECEIVER NUTS
From here, you’re going to install the barrel in the threaded side of your upper and use a steel brush for coating removal on your barrel. Taking out your outer receiver nut and inner barrel retainer nut from your handguard, you’ll unscrew the two nuts from each other.
Coating the barrel threads with white lithium grease (I told you this job could get dirty) will prevent against galling.
Now guide your outer receiver nut on the threads until the nut touches the ejection port cover pin.
You want to unscrew the nut by a single rotation so that the gas hole is aligned with the hole on your upper.
Cover your inner nut with the aforementioned grease and attach your inner barrel nut, tightening it manually.
Insert your gas tube into your inner, outer and upper with the three holes at the end where you’ll be placing your block.
Loosen the screws on the bottom of your block and slide the block so that it’s on the barrel and thread the tube into the block.
Tighten the screws just a bit so it stays stationary while you align the tube your block’s hole with the gas tube’s hole. Tighten the whole thing up and insert roll pin into block and tube alike.
As I mentioned earlier, you can always stick with standard parts for a budget build, but you might want to install free-floating handguards. If that’s the case, I’ve got you covered.
Just pull the delta ring towards the receiver and ease the standard handguard out. You’ll want a handguard tool for this because the spring is going to be under a lot of tension.
Remove your flash hider, separating your upper and lower. Also, remove your scope if it’s in the way so that you can get your upper in a vise.
Next you need to remove your gas block and delta ring. This requires you to take out the barrel nut so have a barrel nut wrench on hand.
Once the delta ring and barrel nut are off, separate them and set them aside. Now you’ll remove the barrel snap ring with a pair of pliers and return the barrel nut since it will be the connective tissue of your free-floating handguard.
Use a torque wrench to torque the nut and test your gas tube, making sure it’s in alignment with your receiver’s port. If it’s a long handguard that you’re utilizing, you want to install a VTAC low-profile gas block.
To mount the handguard, you’ll need two clamshell braces to touch the barrel nut. Once those are installed, the handguard should slide in freely.
If you’ve done everything correctly, the handguard should be a firm, tight fit. You may want to insert screws to keep the locking lever in the right spot.
CUSTOM AR-15 PARTS & ACCESSORIES
If you’ve got money to burn, there are plenty of attractive pieces that you can pick up to trick out your AR-15. These are some of my personal favorites and I think you’ll find they are a great value for the $.
Pistol grips are among the biggest purchases for shooters who enjoy extended firing sessions. If you want a comfortable, customized grip, you can’t go wrong with the M16 grips offered by companies like Bravo Company USA and Hogue.
They’re relatively cheap at around 20 bucks and are very lightweight with ergonomic finger grooves.
Stippling is something that can add a nice texture to your grip or mag. Here is a handy video that shows you how to stipple your AR-15 grip at home.
Aftermarket triggers are another consideration that can assist in upgrading your AR and maximizing your performance. If you’ve got the loot, I strongly recommend getting your hands on the AR Gold Adjustable Trigger.
For under $300, you’ll obtain the cleanest break and shortest reset of any AR trigger and have a significant advantage over other competitive shooters.
Ambidextrous safety selectors are something that most southpaws will appreciate. A variety of companies offer ambidextrous safety selectors, but in my experience you can’t go wrong with those manufactured by Battle Arms Development, Inc.
They’re made from heat-treated steel and come with deeply grooved levers. They can also be customized by applying high-visibility paint.
Anti-rotational pins are one of the more obscure customizations for an AR, but they’re an exceptional upgrade. They’re stronger and longer lasting than standard mil-spec pins. KNS Precision has a terrific non-rotating pin set for $29.99 that prevents wear on your receiver holes.
There are so many things you can do if you want to. From nickel-coated bolt carrier groups to long-range lights and sling mounting hardware.
Basically, you can customize almost any aspect of your AR-15 if you have the time and resources. Whether it’s a custom stock or advanced optics, the possibilities are endless. When I created my own AR-15 build at home, I pimped my AR out with a custom Vortex ® Flash Eliminator from Smith Enterprise, Inc.
HOW TO BUILD A CUSTOMIZED AR
Now that we’ve gone over how to create a budget build, let’s talk about more top of the line builds. If you want a custom precision rifle, it’s a lot easier than you probably think.
Simply purchase a quality AR chassis and single-source your furniture. For instance, you can pick up a WMD Beast Billet chassis and add grips, muzzle device, pistol grip, barrel nut and handguards.
With the WMD Beast, you get a grip screw, safety selector detent, lock washer and detent spring. Pretty much all the little components you’ll need for your build. After you’ve selected a six-position shoulder stock, you can slip it right in without the need for any fancy tools.
After that, all you’ll need is a muzzle device and a barrel nut and you’re good to go. The best option for a luxury model would be the Rise Armament RA-701 Compensator, a recoil-repelling stainless steel muzzle device that’s perfect for the Beast’s match-grade barrel.
BEST AR-15 FURNITURE
For the absolute best overall furniture, I can’t think of a single company that can trump Magpul’s line of parts and accessories. Whether it’s their mil-spec buttstock or their MIAD pistol grip, Magpul’s furniture is awesome.
The MIAD Gen 1 AR gun grip kit sells for around $35.99 and offers an ideal grip. It has a handsome pitch black finish and an internal oil bottle that can be swapped out for other cores. Additionally, it has removable straps for customization.
For a good collapsible stock, you can’t go wrong with Magpul’s UBR Gen 2 collapsible stock. For just under $200, you get adjustable length of pull and a solid cheek weld. It’s multi-positional and provides superior consistency.
Other items you’ll want to consider include rail covers and sling plates. The good news is, these are relatively cheap, even when you’re looking to create a custom AR build. Brownells sells Magpul rail covers for $11.35 while Cabela’s has an ambidextrous sling attachment for $29.99.