Muzzle devices for AR-15s are a funny thing.
Strictly speaking, anything beyond the classic A2 birdcage really isn’t that necessary. The .223/5.56 really isn’t a round that requires help with softening recoil. But yet, a lot of folks will get bent out of shape comparing muzzle device X to device Y.
While building up my first iteration of a marksmanship training rifle, I wanted to do some experimentation. After much searching around and decision making, I purchased the Precision Armament AFAB, which stands for Advanced Flash Arresting Brake.
This is the second generation of the device and replaced the now-discontinued AFAB-mini. Precision Armament revised the design using lessons learned from developing the EFAB, or Enhanced Flash Arresting Brake, which they produced after the original AFAB-mini. Most of the changes focused on better flash suppression.
Precision Armament’s M4-72 Compensator was the best performer in both of TTAG’s Muzzle Brake Shootouts, and the company has a solid grasp on muzzle device engineering. Notably, the AFAB-mini performed slightly worse in the test, but it’s not a dedicated compensator.
AFAB First Impression
The AFAB is 2.225″ long, .865″ wide, and weighs 3 ounces.
It’s made from 416 steel bar and finished with black matte ionbond. In comparison, a standard A2 flash hider is 1.75″ long, .875″ wide, weighs 2 ounces, and is made from 4140 CMV steel. The A2 retails for about $9.
The first thing I’ll say about the AFAB is that I don’t know how they are charging the price they are for it. At just slightly over $100, it’s not an inexpensive item. But the amount of machine work and polish that has gone into this thing is just flat-out impressive.
The machining on the AFAB is top notch. It is very clean, with no sharp edges or burs to be seen. There is a
I often see the AFAB compared to the old Knights Armament Triple Tap, but this really comes down to similar external appearances. Both devices have a visible square pattern cut into the outside.
The KAC device is closer to the Battlecomp in that the inside of the device is hollow. The vents on the KAC device ran in lines from front to back, and the waffle pattern comes from grooves cut around the circumference of the device.
On the other hand, the AFAB’s squares are all individually cut. Each corner of a square has a circular drilled vent down to the bore of the device. The square pattern helps with some of the flash mitigation.
The very top and bottom of the device lack any vents. Vents on the top would contribute to the downward push noted in devices like the Battlecomp. Vents on the bottom would increase muzzle jump and dust signature.
On the inside of the AFAB, you’ll find a series of concentric blast chambers.
This design helps trap expanding gasses and force them out of the vent holes, better assisting with muzzle stability
The AFAB has three tines at the end much like other popular flash hiders on the market. Being a muzzle brake, I wouldn’t expect this to suppress flash as well as something like my AAC Blackout. That said, it does a comparable job to the standard A2 birdcage in field environments.
Precision Armament explicitly tells you NOT to use crush wafers when installing this device.
The internal blast baffles and exit hole at the front have very tight tolerances. Much like suppressors, and any misalignment may result in the bullet impacting the interior of the device.
Instead, Precision Armament suggests using their shim system, sold separately, or a peel washer.
I purchased the shim kit, which is good for installing an average of 9 different devices.
To mount, place the thickest washer on the shoulder of the muzzle and then hand tighten the device. Use the Mk 1 eyeball to determine how much more rotation you would need and choose the corresponding washer according to the included chart. In my case, I needed about 270-280 degrees of rotation. Remove the device.
The kit comes with 18 shims of different thicknesses. Each one has a mark to let you know where it falls in the thinnest to the thickest range. Each step in the series accounts for 20 degrees of rotation of the device.
For the install, you’ll only use a single washer. Simply choose the shim that gives you about 10-20 degrees of travel left when the device is hand tight. Torque the device appropriately (10-20 ft/lb) the rest of the way.
As a tip, you should try to use the minimum amount of torque necessary to index/time the device. Using excessive force can cause problems with crown deformation as the muzzle heats during repeated firing. I recall reading that the Army Marksmanship Unit runs devices just past hand tight on their rifles for this reason.
I always use some Rocksett for extra assurance.
Live Fire Testing
This is a fantastic little compensator.
I installed the AFAB on my 20″ government-barreled BCM equipped with a VLTOR A5 buffer. It was already a smooth shooter before. But is now one of the smoothest and most stable rifles I have ever had the pleasure of getting behind.
The addition of the AFAB feels almost like shooting a laser. From both slow fire and rapid fire, from any position, the sights are extremely easy to keep on target.
I cannot say that the AFAB is much louder or quieter than the A2. But I do note that the report has a sharper pitch to it. The BCM Gunfighter comp on one of my 16″ ARs sounds much louder and has much more concussion.
A 20″ barrel is not really a fair test of a muzzle brake/comp, though. The reduced muzzle pressure and complete burn of powder charge means that just about any device will perform well. The real test is on shorter guns with higher pressures.
From my reading of others who use the AFAB, it performs equally as well for them as it does for me.
I ran this configuration through a couple runs in the MVT HEAT 1 course as well. Nobody seemed to complain about the noise, and the way the gun stayed on target was awesome.
Gas System Pressure
Something else to keep in mind with the AFAB, which is true of all closed chamber muzzle brakes like the Battlecomp, Spikes Dynacomp, Griffin Flashcomp, and others is that there will be a slight increase in bolt carrier velocity as it cycles.
This is due to a little bit more resistance around the muzzle, causing just a bit more back pressure at the port, though nowhere near as much as a full suppressor would. With my 20″ rifle gassed system operating on a full weight BCG and Sprinco Green spring, the effect is negligible.
If you are running a shorter system, then be aware that a closed chamber compensator like this may actually increase your felt recoil at the shoulder. I would argue, however, that this effect is mitigated by the extremely stable muzzle.
From the looks of it, the AFAB has more than adequate flash mitigation for a hybrid device. It won’t perform as well as a dedicated advanced flash hider such as the AAC Blackout, Smith Enterprises Vortex, or a BE Meyers 249f, but it still does a decent job. In fact, TTAG did a more scientific comparison of several flash hiders and hybrid designs, and the AFAB performed well.
There are really two things you need to know about this device.
First, it’s not compatible with a suppressor. Most people going the suppressor route already know that, and will use the muzzle device designed for the can they’ve chosen. But there are some suppressors on the market designed to work around the standard A2 flash hider. Some devices out there, like the Battlecomp or BCM Comp keep the same dimensions as the A2, and are therefore compatible.
This isn’t. It’s too long.
Secondly, a device like this will make your rifle noncompliant with CMP rules for matches. You can still use it in other types of competition, but that kind of high-power shooting is out.
Precision Armament AFAB – The Judgement
Should you buy this comp? I’ll put this in the category of, “Why not?”
The AR-15 is already a soft recoiling weapon. Muzzle stability can be achieved with proper training and without the addition of muzzle devices. With a full size AR in the 20″ class, the AFAB just makes it extremely shootable.
On a shorter weapon, I can see the benefit of a device like this for those who want to move quickly and shoot fast. It helps greatly with muzzle stability, and does not present the usual problems with muzzle flash that comps and brakes are known for.
If you already have a flash hider, comp, or brake that you enjoy shooting, then I don’t think you would see any great benefit of switching to the AFAB.
If you plan on suppressing your rifle in the future, then I would definitely pick a device already compatible with the suppressor you plan to use. There is no using a suppressor with the AFAB.
Pros and Cons of the AFAB
- Very nice machining
- Looks very cool
- Great compensator performance
- Low muzzle flash for a compensator device
- Little increase concussion/noise over A2
- Relatively high cost
- Requires purchase of additional shim kit (so don’t forget to factor it into the price)
- Adds almost half an inch to the length of the weapon over the A2
Rating: Buy it if you want to, as it does great work at the things it is supposed to do. But don’t use it as a substitute for proper shooting form.
If you would like to pick up the AFAB, check them out at Brownells.
Wow. 2 1/2 years without a comment. Very surprising.
Well Matt, I gotta say your article is one of the easiest to read articles that I’ve ever read.
While I may dissagree on some of your oppinions I still value and respect them. Very good write-up.
I have an AFAB on my 16 inch AR and it has been great. I paired it with a hydraulic buffer and it barely moves which helps me as I am just getting into ARs after years with only hunting rifles.