Alexander Arms is a small AR manufacturing company owned and run by Bill Alexander. Alexander has an encyclopedic knowledge of firearms and engineering, and more than once I’ve walked away from a discussion with him, wondering how I could have passed various Materials classes back in college without the stuff he’d just told me. To say he knows his stuff is to vastly understate his grasp of firearms.
The .50 Beowulf became public back at the turn of the 21st century, when Alexander decided the various big-bore AR cartridges all had something wrong with them. He started with the .50 Action Express as the base cartridge. To make it fit an AR-15 magazine and feed properly—and provide the performance he wanted—Alexander lengthened the .50 AE case from a nominal 1.285 inches to 1.65 inches. At the same time, he had to reduce the rim diameter from the .50 AE’s .514 inch down to .445 inch.
Why the changes to the case dimensions? The stubby .50 AE would have bounced back and forth inside the AR magazine and thus never be in the proper location for reliable feeding. And the rim diameter of the .50 AE was far too large for the bolt of the AR. Alexander reduced it to the same diameter as the 7.62×39 and his later 6.5 Grendel cartridge, as he had a lot of experience making improved bolts—accomplished via different alloys and heat treatment in the case of the Beowulf.
The primer stayed the same. It is a Large Pistol primer, although the reloading data for the .50 Beowulf recommend a Large Pistol Magnum primer. Depending on the bullet weight, type of powder and desired velocity, the primer has to ignite between 32 and 51 grains of powder. That’s asking a lot of a standard pistol primer, so Alexander Arms loads with, and recommends the use of, magnum pistol primers.
The original design specs for the .50 Beowulf called for a 400-grain bullet, of .500-inch diameter, at 1,800 fps. This out of a straight-wall case (there’s a bit of taper for reliable feeding, but not much) operating at a controllable low pressure of 33,000 psi.
Alexander’s goal was a .50 caliber cartridge that wouldn’t require any rifle modifications, but this was not to be. One detail that had to be changed was the ejection port cover. The thumb-sized empties would sometimes bind on the ejection port cover or its opening. So Alexander simply left off the cover and opened the port to provide a reliable exit for expended brass. It is wider top to bottom, but essentially the same length front to back as that of a 5.56 rifle.
The barrel extension of the .50 Beowulf barrel is modified so it will properly feed the fat, stubby cartridge as well. But the exterior dimensions of the barrel extension are standard AR, so the Beowulf upper receiver does not require modifications besides the ejection port to work with the .50 cartridge.
By now you’re probably getting the impression that .50 Beowulf rifles aren’t exactly new, and you’d be right: Alexander Arms has made rifles for it before. But none of them were like this.
New Tactical Model
The new Tactical model I received for testing has been redesigned with a slick and modern new handguard, a new finish, and a barrel that has been threaded at the muzzle for a flash hider, brake or suppressor of your choice. As with so many things Alexander Arms, the sum of the improvements is greater than what each change might suggest.
The lower is pure AR, distilled by Alexander Arms and tuned to perfection. It is machined from a forging, and a Bravo Company B5 Systems collapsible stock is installed on the receiver extension. The B5 is an evolved SOPMOD stock, with a pyramidal-shaped cheekpiece and a rubber recoil/non-slip pad on the rear. The receiver extension tube is mil-spec diameter and has six selections for length of pull.
You have your choice of either the Geissele SSA trigger set or the Alexander Arms Tactical trigger. This one came with the AA Tactical trigger installed. It’s a clean, crisp, single-stage trigger that dropped the hammer at just over four pounds—and when firing such a hard-hitting cartridge I’m not sure I’d want a trigger much lighter than that.
Alexander Arms provides four-, seven- and 10-round magazines that have been designed to work with the Beowulf, and a seven-rounder ships with the rifle. Alexander tells me it is entirely possible that magazines you have on hand will work, as the tweaks he makes are small, but I see this as poor economy. How much expensive .50 Beowulf ammunition are you going to shoot in order to determine which of your existing magazines will feed reliably?
The upper is where all the drama—and power—originates. It is a standard flattop, machined from forgings, with the aforementioned widened ejection port. Inside the receiver, Alexander Arms uses a mil-spec bolt carrier, complete with chrome lining in the bolt recess. The bolt is made by the company, with a breech face machined to the .50 Beowulf rim diameter.
The .50 Beowulf barrel is made of a chrome-moly steel alloy. It’s 16.5 inches long and looks impossibly large underneath the Manticore Arms Transformer handguard. While the barrel diameter may seem excessive at .795 inch at the back of the brake, remember there is a .500-inch hole down the middle. The rifling has a 1:20 twist rate, which is fast enough to stabilize .50 caliber bullets weighing up to 400 grains.
The low-profile gas block is located at the mid-length position. This is a new location, relatively speaking, for the gas port. The mid-length allows for a carbine-length rifle but with a gas system less persnickety about port pressure than carbine-length systems can be. The muzzle is threaded for a muzzle brake or suppressor, and the threads there are 49/64-20 RH.
Why such an odd thread?
“There’s a .50 caliber hole down the center of that barrel,” Alexander says. “We wanted to leave plenty of wall thickness while also providing threads strong enough to take the impact of the gases. Also, there’s no way someone can fit a suppressor made for a smaller caliber on there.
“Suppressors for the .50 BMG are almost as big as the rifle itself and have a significant weight penalty. The Beowulf doesn’t have a lot of muzzle pressure, so I’m working on a suppressor that will be Beowulf specific.”
When you order, you have your choice of three different brakes, some threaded and some permanently attached for those who live where threaded muzzles are not permitted.
The Manticore Arms Transformer is a slim, cleverly designed handguard. Its base is a tough, rigid skeleton to which you attach filler panels. These can be KeyMod, M-Lok or just filler panels with a non-slip pattern in them. There are also aftermarket makers of panels for the Transformer, such as VZ Grips, who can make even more patterns and offer them in other colors as well.
The Transformer also has a raised rail section out front for mounting a front sight if you want irons. Other than that, it is as slim, easy-to-grasp and non-slip a handguard as you’d ever want on a rifle.
The muzzle brake is the Tank brake, and it looks just like you’d imagine from the name. It uses a pair of expansion chambers and blast baffles for the gases to work on. Gases from the muzzle, jetting forward, strike the internal baffles of the brake, and the impact pulls the rifle forward. The rifle has already started moving by then, but the gas impact offsets much of the movement after that moment in the firing cycle. Because the Beowulf operates at such a low pressure (relatively speaking) compared to the 5.56, the gases need a lot of surface area to push on to counteract the shove the Beowulf is going to give you.
The Tank brake does not reduce the upwards movement of the rifle; you will have to deal with that yourself. As it turned out, the blast to the shooter isn’t too bad, but you do not (let me be clear: you do not) want to be standing a couple feet to either side of the shooter. Under a covered firing line, the muzzle flash the brake produces could be seen by bystanders on every shot.
While Alexander Arms makes the .50 Beowulf without a muzzle brake, I’m not sure I’d want to shoot it much without one. Unbraked, the felt recoil would be stout. If we use Power Factor (bullet weight times muzzle velocity) as an estimated measure of recoil, a standard AR-15 in .223/5.56 produces a Power Factor of 176. The .50 Beowulf delivers 510 to 640, depending on bullet weight—basically 20- to 12-gauge slug levels.
Along with the rifle options, including the various panels and the brakes, Alexander Arms also gives you a choice of rifle color: black, olive drab and flat dark earth. These are all Cerakote finishes applied after the aluminum has been anodized, resulting in a better looking finish.
For accuracy testing I installed a Trijicon VCOG scope on the rifle. The VCOG has its own mount, which simplifies mounting. Complete with a battery to power the illuminated reticle, the rifle and scope tipped the scales at nine pounds, two ounces.
I asked Alexander about optics surviving on the Beowulf, and he told me that if your scope is going to have a problem aboard the Beowulf, you’ll usually find out in the first box or two of ammo. I went through a lot more than that, and the scope survived.
Considering the power I was about to unleash, I considered bolting on any extra, heavy, gear that might fit the M-Lok or KeyMod panels, but as it turned out, the muzzle brake worked well to tame the recoil.
You’d think that hurling a .50 bullet out of a thumb-sized cartridge would result in only average accuracy. Not so. My range was a sea of mud when I tested the rifle, so I set targets up at 50 yards, where one ragged hole became the norm. Plinking on clods of dirt or other small targets of opportunity on the 100-yard berm earned the Beowulf Tactical the nickname of “Vaporizer.” Pressing the trigger produced an impressive splash of dirt and mud—and the atomization of said target.
Alexander is good, really good, at design and manufacturing, so there’s no magic involved in any of this. His company works hard to make first-class rifles, and if you want a real thumper, a big-bore rifle to impress, this is it. Still on the fence? There are plenty of loading data, and loading dies are readily available.