With AR-15s it seems you can pretty much build whatever you want.
From super lightweight PDWs with 11.5 inch barrels and collapsing stocks to 24 inch equipped Special purpose rifles with carbon fiber barrels. If you dream it you can build it.
Of course, just like car enthusiasts have a tendency to be most excited about building classic cars, a lot of firearm enthusiasts want to build classic AR-15s. One of the most prolific classic AR-15 models is the M16A2.
The M16A2 holds a special place in my heart because it was the rifle I carried through boot camp, and I was in one of the last boot camp cycles to issue the A2 to recruits. The M16A2 was a Marine Corps led project to improve the M16 after its Vietnam experience.
It served from the mid-80s well into the War on Terror. It can still be found in reserve units and marksmanship units. It’s also a common sight in the service rifle division at NRA High Power matches.
Today we are going to look at what it takes to build an M16A2 replica, an AR15A2 if you will. I’ve seen a lot of people asking about it, so I’ve assembled a list of the parts you need to build an M16A2.
Or if everything seems a little too difficult…Stag Arms has got you covered!
The Unique Upper
What really sets the M16A2 apart from modern AR 15s is the carry handle equipped upper receiver. This carry handle upper receiver gives the M16A2 a very unique profile, and makes it stand out in a world of flat top uppers.
This can be one of the harder parts to find, especially if you really want that classically fixed carry handle instead of a flat top with a mounted carry handle.
Oddly enough I’ve never seen someone actually carry the gun by this handle. Personally, I know the idea of using the carry handle to carry the rifle would have resulted in ‘corrective action’ in boot camp.
The entire carry handle concept is odd, and I think that’s what makes the retro M16s so unique.
Luckily, we have two options. One’s the classic choice, while the other is a more affordable option for those on a budget.
For a more authentic M26A2 clone, I suggest the Colt A2 upper receiver. This is as close to the actual military upper you are going to get your hands on.
If you’re looking for something a bit less expensive, DPMS makes a very affordable and noteworthy model that’s true to the standard A2 design.
The M16A2 upper is equipped with a robust rear iron sight with two apertures and tons of adjustment potential. The above uppers are both stripped, so you’ll need to purchase the rear sight separately.
You’ll also need a standard upper parts kit to finish your rifle, including the dust cover and forward assist with the necessary springs and pins. Aero Precision makes excellent guns and gear, and this kit is a bargain.
The Barrel and Beyond
A 20 inch barrel on an AR makes the gun sound like a beast in a world of carbines, SBRs, and AR pistols. The 223/5.56 round was designed for use with a 20-inch barrel so you’ll be getting optimum performance.
20 inch barrels are easy to find, but I suggest Faxon because I know they are high quality. A barrel typically isn’t something to skimp on.
Once you’ve got a plain barrel you’ll need a few more things to make it an A2 barrel. First, you need that fixed front sight. Daniel Defense not only makes one but makes one of the most affordable models.
Alternatively, if you want something a little simpler you can get a 20-inch barrel with a fixed sight base already attached by Brownells’s own brand of premium barrels.
Regardless of what route you go, you’ll also need a gas tube and A2 flash suppressor. The rifle length gas tube is actually a major advantage of the 20-inch barrels. You get less recoil, and the gun runs cooler.
The A2 flash suppressor is one of the best flash suppressors out there and acts as a compensator as well, plus they’re common and cheap.
You’ll also need those famous polymer round handguards. Rail systems on rifles were only a dream when the M16A2 entered service and rifles were kept nice and light using polymer handguards. Rock River Arms makes an excellent set of classic round handguards that use triangular caps.
You’ll also need a few other miscellaneous small parts:
- Handguard Liners
- Delta Ring Kit
- Barrel Nut
- Barrel Indexing Pin
The Rifle’s Heart and Soul
At the core of the rifle, resting comfortably and softly in the upper receiver is the bolt carrier group. The bolt carrier group is easily one of the most important parts of the rifle, and you have literally tons of options. If you want more specific info, check out our article on BCGs here.
However, if we are being legit with our A2 build we gotta go with the classic M16 full auto BCG, with a mil-spec phosphate coating. You have tons and tons of options, so the real question is which one do you want?
Personally, if I’m going legit A2 I’m going with a Colt BCG.
It’s a little pricey, I know, but there are less expensive alternatives. Brownells, for example, makes a very simple and very affordable option.
The Complete Upper
If you appreciate things nice and simple, don’t have a ton of time, or are just a little lazy you can also go with a complete upper option, with the right upper, barrel, gas tube, bcg, etc. included.
This one is from Anderson, who famously makes some of the most affordable, but still quality, lower receivers.
That’ll about do it on our upper receiver so now we can focus on the lower half of your A2 build. The good news is choosing a lower receiver is pretty easy to do. Unlike an upper, you can basically use any standard mil-spec lower receiver.
The standard AR 15 lower receiver hasn’t changed since the A2 so you can throw a dart at the Brownells catalog and pick whichever receiver it lands on. Personally, I’m a fan of Spike’s lowers. They are well priced, easy to find, and high quality.
However, any forged 7075 T6 aluminum lower with an anodized finish will be technically correct. Stay away from lowers with short throw safeties, and stay far away from polymer if you want a legit M16A2.
You’ll also need to put the clothes on (or in I guess) that stripped lower. For this, you again have dozens of choices. If we are keeping it legit you can go with the Colt Lower parts kit.
This kit does not include the pistol grip or trigger. Both are easy enough to find.
If you are looking to build an A2 for service rifle competition, then the Rock Island Match trigger is a great option for you. The Rock River Arms Match trigger provides a clean and crisp pull that comes in at about 4.5 to 5 pounds. It’s a two-stage trigger that is much cleaner and smoother than any mil-spec trigger.
For those who want to go the simple route, there is are complete lower kits that are both affordable and easy to find. Bushmaster has a great classic mil-spec option that’ll fit in an A2 build.
And for competitors that want to make their build easier, Rock River Arms also has a complete lower kit that includes their Match Trigger.
If you want to make your build as simple as possible, there are always complete lowers with an installed lower parts kit. This will save you a bit of time, and likely some frustration from that irritating front pivot pin.
Finally, we get to the rear of our A2 build. The A2 again has what some would consider an antiquated stock. It’s fixed!
Oh, the humanity! It doesn’t collapse, fold, and it’s not easily removable. However, it is quite durable, provides an excellent cheek rest, and even has a compartment to stow things in.
Few companies make authentic A2 stocks, but High Standard is one of them. The High Standard stock is completely mil-spec, down to the aggressive triangular texturing on the end of the stock.
You’ll also need a rifle buffer, rifle buffer spring, and rifle buffer spring tube. All are somewhat odd in the days or carbines and collapsible stocks. Luckily, Brownells piled everything together in one kit, making this much easier.
Of course, you are going to need some mags to make the whole thing run right? Well if it’s an A2 clone you can tell those Lancers, Pmags, and Hexmags they gotta go. No for an A2 build you gotta go old school aluminum.
The Brownells brand aluminum mags are mil-spec, cheap, and available in multiple quantities.
For those poor souls in states with capacity limits, Brownells has ten rounders available as well.
Now the following items aren’t needed for an M16A2 clone, but they can add a little pizazz to your build. These accessories hark back to those easier days, where rails weren’t a thing, and our version of MLOK was duct tape.
Bayonets are actually still issued with the M16A4 and the M4 rifles. Bayonets have been part of the military’s inventory for hundreds of years, and will likely remain so, but do you really need one?
Probably not, but a bayonet definitely adds something extra to the build. As much as I love things that go boom, I also like pointy things. I’m tossing two bayos up here because the M16A2 served long enough to be issued both.
Ontario M9 Bayonet
The M9 bayonet is the bayonet of the United States Army. It doubles as a combat or general utility knife. A bayonet has to be extremely well made for it to function correctly. Good thing this bayonet is designed to be used as a spear point.
Ontario was one of the many companies who was contracted to produce the M9 bayonet and they still manufacture the design. If you’re buying a bayonet you might as well buy one from a company who makes it right.
Ontario OKC3S Bayonet
This is the bayonet I know and love from my time with the Marines. The OKC3S is essentially the famous Marine Corps KA-BAR turned into a bayonet. It features a 7-inch blade with a little serration at the end. The OKC3S is issued to almost every Marine carrying a rifle and they were even used in Fallujah.
Marines still train with bayonets and are required to prove proficiency to obtain their tan belt and graduate boot camp.
Barska 4×20 Electro Sight
This replica of the classic Colt scope proves you can toss an optic on an A2 without issue. Barska produces an affordable Colt replica that gives the user a 4 power magnification, and a sleek old school look. The Barska sight isn’t a go to war optic, but it’s perfect for capturing that old school cool look and feel of the A2 platform.
In a day where elaborate slings rule the roost, the classic GI sling feels a bit underwhelming, but this style of sling has served for decades! It’s simple, reliable, and the M16A2 platform works perfectly with it. It’s another complete the look accessory.
That’ll Do For an A2
M16A2 builds, and retro builds in general, are a very popular trend in the AR world. Brownells is even selling old school AR receivers and furniture for A1s. Just a quick glance at R/guns reveals how popular retro builds are.
Plus you can get a full retro kit from Stag Arms.
It’s odd to see so many people clamoring for carry handle equipped uppers, but I guess everything is cyclical.
If you need a more modern AR-15, you’ll want to read our Complete AR-15 Buyer’s Guide!
Readers, do you guys and gals have an interest in retro ARs? What about retro guns in general? Let us know in the comments!