In a day and age in which AR platform rifles are only getting smaller, I’m betting there are plenty of shooters who’ve never tried an AR-15 with a 20-inch barrel. The 16-inch standard AR15 carbine seems to be the most common AR these days, with shorter lengths also being quite popular. It’s a shame how few people know how brilliantly smooth an AR-15 with a 20-inch barrel can be.
A long time ago I was a young Marine infantryman armed to the teeth with a bevy of issued weapons including my beloved M240, my Beretta M9, a Mossberg 500, and of course an M16A4. After I got out of the service I did what everyone else did and bought an AR carbine and didn’t look back for years. But I’m glad I finally did.
The market for AR-15 rifles with 20-inch barrels is still very much alive. The clone market is one source of demand and for those looking to clone military rifles. PSA, FN, Bear Creek Arsenal and, as you can see here, Aero Precision are making classic M16A2 and A4 style rifles.
This is not a production M16A4 clone rifle. You have two options if you want to build an M16A4 style rifle from Aero Precision. Aero makes a complete rifle equipped with a quad rail that lacks a carry handle and is sold by Brownells. The second is this build which is just the Aero AR15 20″ inch upper and M16A4 lower. All I added was a Stealth Gear charging handle and an Aero Precision 5.56 NATO bolt carrier group to complete the upper.
Is it an M16A4? Not really, but kind of.
I went with the lighter, non-railed variant with the awesome carry handle sights. It still features the standard A4 goodies, including the flat top upper that’s just begging for an ACOG.
The Aero complete lower receiver features some semi-accurate markings with Property of USA and M16A4 being stamped on. These aren’t 100% accurate, and the only way I know of to get 100% accurate markings involves an 80% lower and an engraver. You do get the tease of a burst inscription, which is a nice touch.
Why a Full-Size Rifle AR?
The .223 Remington round was built around a 20-inch barrel, which gives users of this rifle a few advantages. There’s a little extra velocity which gives you at most a 200 FPS advantage over a 16-inch barrel, but often delivers less than that.
There are reportedly some steel armor plates that can withstand an M193 from a 16-inch AR-15 but not from one with a 20-inch barrel, but I can’t independently verify that. The biggest advantage is just the smooth shooting nature of a full-length AR-15.
There is hardly any recoil from this rifle. It’s super-smooth and comfortable to shoot. Muzzle blast and concussion are almost nil, as is muzzle rise and muzzle flash. This is one of the most comfortable rifles I’ve ever fired.
Back in the day, I didn’t really appreciate my ole A4. Cool guys had M4s, plus I was already issued far too many guns and the rifle seemed superfluous in the face of my M240. However, these days I’m starting to appreciate the traits of the M16A4 and full-sized ARs in general.
The main reason I wanted a full-sized AR, though, was nostalgia. I handled an Aero Precision M16A4 at SHOT Show and had wanted one ever since. While it lacks an ACOG and a KAC rail, it’s almost a perfect replica of my service rifle.
The A2 style stock, the dynamic sights, the bayonet lug, that horrid standard A2 grip and, of course, the A2 flash suppressor. All features I am intimately familiar with.
The Stability of the A2 Stock
A lot of people, especially smaller-framed Marines, really didn’t like the A2 style stock. Especially when you mix in the bulk of body armor and the inch or two it adds. However, my large frame never minded the long A2 stock. It fits me just right.
The Aero stock is rock solid and provides an excellent cheek weld. You can lock this stock in the pocket of your shoulder and tighten down and get a natural sight picture. In a pinch, you could slam someone’s face into it and it would be an effective melee weapon.
This Aero Precision model sports the A2 style ribbed texturing on the stock, as well as a compartment that holds a cleaning kit. Brownell’s also has leaded weights to help decrease recoil and make for a heavier stock for aforementioned butt stroking.
It’s a very stable rifle stock that stays in your shoulder as you shoot. You can fire rapidly and the gun won’t move at all.
The Aero Precision’s handguards are classic A2 style plastic. They’re long and round and are pretty damn comfortable to grip. You can do the most exaggerated C-clamp grip very easily if you so choose. They do tend to heat up when you start spitting lead downrange and gloves might be a good choice if you’re shooting a lot in a short period of time.
Shooting the M16A4 Rifle
The gun has also run reliably one hundred percent of the time. It’s eaten mostly Hornady LE Training ammo, which is lacquered steel case. It’s also been fed a steady diet of hundreds of rounds of Monarch Ammo from Academy. To finish it all off I went through my final 200 rounds of Wolf Gold .223.
I broke out the old M16A4 manual that you can find here (PDF) and followed the 25 meter zeroing procedure. This is the Army’s procedure and the Marines use a 36/300 zero.
I had a 25 meter zeroing target I picked up somewhere so I bit the bullet and took the Army’s route. I assumed the prone and followed the procedure to obtain a battle sight zero.
There is a real joy in creating a group that looks like a three-leaf clover. Yeah, it’s only 25 yards and this is a full-sized rifle, but that kinda joy is irreplaceable. So much so that even after I had zeroed the gun, I kept shooting those 3-shot groups. The trigger isn’t match grade, but it feels like it’s on the higher end of mil-spec.
I moved back to the 100-yard line to quit sandbagging it. From a standing position, I produced this group on a Sage Dynamics target. For a sub 1K rifle, in an unsupported standing position, and with just iron sights I’m plenty happy with that.
At 100 yards in an unsupported prone position, I achieved this group. I disappointed myself with that flyer, but you live and you learn. At this range, I couldn’t see the actual lines on the target so just aimed for the white sheet of paper.
Making things a little more tactical I ran a few drills from my glory days as a Marine and utilized the Pocket Pro 2 to time myself. I wanted to see how the rifle handled as a more modern combat rifle.
I fired a Failure to Stop Drill, a Box Drill, and several Snap Drills aiming for the head. I fired all drills at 15 yards.
Failure to Stop Drill Times
- 1.65
- 1.50
- 1.43
Box Drill Times
- 3.54
- 3.65
- 3.41
Snap Drills Times
- 1.13
- 1.00
- 1.02
The Aero M16A4 is a rifleman’s rifle, and while the current battlefield is ruled by the M4, the M16 is still an excellent design if your goal is to design a full-sized rifle. There is a lot to be said about the differences between the rifles and their purposes.
In many ways, the M16A4 and A2 were designed for a war that was never fought. A war where engagements against the red hoard were fought across open fields and 500-yard shots on man-sized targets were expected and troops would be dialing in windage and elevation corrections mid-battle.
The Marine Corps is now issuing the M4 to all grunts the M16A4 is still issued to non-combat troops. It’s the last full-sized, general issued rifle and will hold a special place in my heart.
Aero Precision has done an excellent job reproducing the rifle and I’m happy they offered a non-rail ‘slick’ upper receiver for those of us who just want a quality 20-inch barreled AR-15 that’s light and handy.
The Aero Precision version feels better-built than my issued M16A4. Then again, it wasn’t run through a hundred different Marines on a dozen different deployments and tons of field ops.
Specifications: Aero Precision M16A4 Rifle
Caliber – .223, 5.56 NATO
Operation – Direct Impingement
Capacity – 5 to 150 rounds
Barrel Length – 20 inches
Overall Length – 39.63 inches
Sights – M16A4 carry handle and Fixed Front
Twist Rate – 1:7
Weight – 7 lbs 8 ounces
MSRP – Upper $450 Lower $250
Ratings (Out of five stars):
Accuracy * * * * *
Let’s see, a long sight radius, a rock-solid stock, and a decent trigger are combined here to produce a very accurate weapon overall. It’s accurate for both long-range a well as close quarter’s shooting.
Ergonomics * * * *
The AR-15 platform is very ergonomic and the controls are placed well. It’s a living example of how to design a rifle ergonomically. I took off one star because I know the A2 stock is too long for many shooters.
Reliability * * * * *
It eats and eats and eats without issue. The gun has given me zero issues with various types of ammo. If they haven’t cracked the AR-15 design yet they never will.
Customization * * * *
It’s an AR-15 so do whatever you want. You can swap anything, but I doubt many people are buying these rifles to do a lot of accessorizing. I took one star off because this model doesn’t have a rail system (which was a conscious choice).
Fit and Finish * * * * *
The upper and lower’s finish match perfectly. The finish is a standard anodized black and while it’s not glamorous, the gun looks excellent. The A4 has an attractive retro look I can’t help but appreciate.
Overall * * * * *
I love this gun. It might be the nostalgia talking, but the Aero Precision M16A4 is a real winner as far as I’m concerned. It’s a fun-shooting, accurate, and reliable rifle that I adore.