The .50 Beowulf from Alexander Arms

By David M. Fortier

As of late there has been a great deal of controversy over the supposed shortcomings of our current issue 5.56x45mm NATO M855 cartridge. Whether the problem is a load failure, cartridge failure, operator error, or simply asking more than is reasonable to expect from such a cartridge I’ll leave for others to debate. One thing for certain though is that heavy, large diameter bullets put big holes in people. This was most evident prior to the Army’s adoption of the .30-40 Krag at the end of the 19th Century. The terminal effects of cartridges like the .45-70 and .50-70, as well as the older .58 caliber rifled muskets, were most impressive whether on man or beast. These old black powder cartridges drove large caliber soft lead slugs at moderate velocities and did dreadful things to flesh and bone.

A fine example of their performance can be seen in a shot made by a French Imperial Marine named Robert Guillemard. While stationed on the pitching mizzenmast of Redoutable he punched a .69-caliber hole through Admiral Horatio Nelson’s chest. When flint struck steel England’s greatest naval tactician was cast down as if by Old Testament fire and brimstone. Large-caliber slugs at moderate velocities have many drawbacks and shortcomings, but poor performance on flesh and blood is not among them.

For the most part, large-caliber rifle cartridges for military or law enforcement use disappeared a century ago. However in the recent past, for highly specialized use, a few experimental short .458 cartridges were developed, including one by Norm Chandler. On the other side of the pond the Russians developed and fielded their 9x39mm cartridge firing heavy 9mm projectiles at sub-sonic velocities. I had a chance to interview several members of a SPETsNAZ SOBR team on this round’s effectiveness. Professional soldiers, they were veterans of Chechnya as well as the ongoing fight against organized crime on the streets of Moscow. One carried an A91 assault rifle while their sniper deployed with a suppressed VSK94 sniper rifle. Both of these weapons are chambered for the Russian 9x39mm cartridge.

This sub-sonic round is based upon the well-known 7.62x39mm and is currently used in a number of specialized Russian weapons. Designed for (realistic) use out to 200 meters, it drives a 9mm 250-grain projectile at 950 fps. Its purpose? To provide a cartridge that’s not only controllable but also easily suppressed with greater terminal effect than conventional handgun or rifle FMJ projectiles at close range. Also, just as over penetration in urban police operations is a very real liability here in the U.S., the same is true in Russia. For urban situations the 9x39mm cartridge offers an alternative to the West’s use of either 9x19mm MP5’s or short-barreled 5.56x45mm weapons. While this cartridge can defeat body armor if required (the Russians claim it’s AP loading will cleanly penetrate both sides of a U.S. Kevlar helmet at 400 meters) it offers less penetration and chance of a ricochet than conventional 5.45x39mm and 7.62x39mm rifle rounds. For situations where penetration is neither required nor desirable they use a frangible load. While interviewing them one thing quickly became quite clear, they were extremely impressed by this cartridge’s terminal effect on target.

While the Russian 9x39mm is an older and well-developed cartridge, one relative newcomer is the British-designed .50 Beowulf. Featuring a straight wall case and drastically rebated rim the .50 Beowulf was specifically designed to operate in a modified AR-15 carbine. The result is a lightweight autoloading carbine capable of driving a 334-grain .50 caliber slug at 1,900 fps. The progeny of Alexander Arms LLC, the .50 Beowulf performs similar to a compact, magazine-fed semiautomatic 12-gauge shotgun loaded with slugs. Except of course, unlike most 12-gauge slug guns, with the Beowulf you can easily make hits at 200 yards. Its intended usage is that of a force protection rifle deployed “when something must get knocked over or stopped,” such as a motor vehicle.

Alexander Arms LLC introduced the .50 Beowulf cartridge a little over a year ago. Since then Alexander Arms LLC has introduced another model with a free floated barrel, several different options, as well as a number of new .50 Beowulf loads. Recently SAR had a chance to evaluate this new model, their Precision rifle, decked out with some options including their new muzzle brake. In addition SAR had a chance to fire three of their new loads.

Originally located in England, Alexander Arms LLC was a Research and Development Consultancy working predominantly on military wares for the British MoD. Their contracts covered everything from chain guns to tiny Personal Defense Weapons (PDW). In their spare time they set out to build a large caliber AR. Initially they tried utilizing a .50-70 case with the rim spun down to .308 dimensions and the overall length shorted to 1.5 inches. When this proved a dead end they tried working with .404 Jeffrey brass, but it too failed.

Next they tried some unfinished .50 AE brass. This had neither an extractor groove cut into it nor had it been trimmed to length yet. They ended up spinning the case head all the way down to 7.62x39mm dimensions. While this drastically rebated the case head it allowed them to use proven off-the-shelf 7.62x39mm bolts. These offer a substantial increase in strength, longevity, and safety over a bolt who’s face had been opened up to accept a larger diameter case. Next they trimmed the cases down to fit into a standard AR-15 magazine, and topped it with a 325-grain Speer HP. After refining the angles of the cartridge base for increased reliability the .50 Beowulf was born.

The result of their big bore developmental work is a fat, straight walled case that looks a bit odd due to the noticeably rebated case head. Dwarfing both its parent, the .50 AE, as well as a 5.56x45mm, it’s an impressive looking round. Currently Alexander Arms offers six loads in this caliber.

1. 325-grain Speer Hollow Point at over 1,900 fps
2. 400-grain Hawk Flat Point at 1,800 fps
3. 400-grain Hawk Flat Point Low Impulse at 1,300 fps
4. 325-grain Barnes X
5. 334-grain FMJ
6. 334-grain JHP

The weapon chambered for this proprietary cartridge is a short-barreled AR-15 carbine. The model SAR received in for testing, their Precision rifle, also featured as options a muzzle brake, Ace Ltd. ‘Boom Tube’ buttstock, Harris bipod, riser block for mounting optics, 5.5x50mm Trijicon ACOG, and a Quake Industries sling. Handling it the first thing one notices is the large muzzle brake. This unit has an outside diameter of 1.03 inches and is approximately 3.375 inches long. The inside of this unit is a tapered cone running from .55 inches out to .78 inches. The brake features five rows of six 0.25-inch holes with a right-hand offset at 15 degrees. The design of the brake is intended to make use of not only the exhaust gas from the cartridge itself but also the air in the barrel ahead of the projectile. This is necessary due to the lack of high velocity gas. Also of interest is the fact that while brakes for military and LE guns are threaded in place Alexander Arms has found it possible to “glue” brakes on guns intended for commercial sales. So attached they say that “it would require 16,000 pounds of force to rip the brake from the muzzle.”

The muzzle brake is mounted onto a 16.1-inch chrome moly barrel featuring 6-groove rifling with a right-hand twist of one turn in 19 inches. Barrel diameter at the breach is 0.980-inch and after the gas block this steps down, rather than tapering, to 0.775-inch at the muzzle. The muzzle features a 45-degree mirror crown. Approximately 5 inches back from the muzzle is a custom gas block manufactured from 4140 chrome moly. This was securely mounted via two steel pins. Surrounding the barrel is a Rock River Arms free floating aluminum handguard. Onto this was mounted a rugged Harris bipod.

The barrel is attached to what is essentially a standard A3 flattop upper receiver. The only noticeable difference being the greatly enlarged ejection port lacking a spring loaded cover. The upper receiver is made to Alexander Arms specs, and as such the ejection port is machined to proper dimensions during the original manufacturing process. So the port on a 5.56x45mm upper receiver is not simply opened up. However, no ejection cover is currently mounted, although they may introduce one in the future. The barrel extension is also made specifically for the .50 Beowulf and features a 38-degree, as opposed to a 45-degree angle, on the feed ramp.

Inside the upper receiver one finds a 7.62x39mm bolt, also built to their specifications. However, the carrier, firing pin, and other parts are off the shelf milspec units. The lower receiver is a high quality 7075 T6 forged aluminum unit. It’s a standard piece with all milspec fire control parts and an A2 pistol grip. However in place of the standard A2 stock our test rifle sported an Ace Ltd. “Boom Tube” stock which is adjustable for length-of-pull and sported a rubber buttpad. The end result is serious looking carbine 36.25 inches long tipping the scales at approximately 7 pounds.

Feed is from steel magazines manufactured by Pro Mag. Basically a slightly modified 20-round 5.56x45mm magazine, they’re of good quality and hold seven rounds. In the future Pro Mag will be introducing dedicated .50 Beowulf magazines. It should be noted though that ten rounds will fit in a modified 30-round 5.56x45mm magazine and that Alexander Arms is working on a 12-round magazine for military/LE use. During testing SAR evaluated the .50 Beowulf for fit and finish, intrinsic and practical accuracy, controllability, flash signature, handling, and reliability. The upper and lower receivers had been manufactured by Rock River Arms who are known for their high quality AR’s. It was nicely finished, everything operated smoothly, and it looked good. One thing that does catch your eye is Alexander Arms address marked into the lower receiver, U.S. Army Radford Arsenal.

To test the rifle for intrinsic accuracy it was shot off a Wichita rest at 100 yards. Six 5-shot groups were recorded and velocity readings taken 12 feet from the muzzle with an Oehler 35P chronograph. Ambient temperature was 20 degrees F. There was a 2-3 mph wind from 7-9 o’clock with gusts up to 5 mph. Accuracy testing was performed using Trijicon’s latest 5.5x50mm ACOG. This unit features both higher magnification, 5.5x, and a larger objective, 50mm, for enhanced light transmission and improved resolution. In use this optic proved well-built, rugged, and easy to use. Color rendition, resolution, contrast, and light transmission were excellent.

Having tested an early .50 Beowulf lacking a muzzle brake I was interested in seeing how much of a difference there was in recoil and muzzle rise. Driving a 325-grain slug at 1,900 fps out of 7-pound carbine lacking a muzzle brake generates some healthy recoil. However, the Alexander Arms unit worked very well and cut felt recoil substantially in my opinion. However we did feel muzzle rise was still an issue and this gun would benefit greatly from a forward vertical grip.

Off the bench the Beowulf acquitted itself quite well. Best accuracy was obtained with the 334-grain JHP load that averaged 1.5-inch 5-shot groups. Velocity of this load ran 1,861 fps. The 334-grain FMJ load averaged 1.73 inches at 1,848 fps. The 325-grain Speer JHP averaged 1.75-inches at 1,848 fps. Lastly the Barnes X averaged 2.25 inches at 1,769 fps.

Posting some plain white IPSC silhouettes at 330 yards we decided to push the .50 Beowulf to its outer limits. This is a short-range cartridge due to its rainbow-like trajectory. The ACOG is equipped with an illuminated chevron reticle with holdover marks out to 800 meters calibrated for 5.56x45mm NATO M855 ball. With the range and wind accounted for, I proceeded to fire 5-shot groups on three silhouettes at this range. Average group size came in at 7 inches.

Next I ran it through some drills at 15-75 yards. Here I popped the 5.5x50 ACOG and riser block off and mounted a compact 3x24mm ACOG. I also removed the Harris bipod to lighten the front of the weapon. With that done I got to work rapidly engaging multiple targets. The Beowulf proved easy to hit with and punched .50 caliber holes wherever you pointed it. While it does jump quite a bit, even with the muzzle brake, you can control it and make it do what you want. The carbine is short and light so it handles extremely well. It was an easy piece to carry all day in the field, maneuvered well indoors, and was quick to get into action. While the magazines only hold 7 rounds they are at least easy to change. Reliability throughout testing was flawless. Magazines inserted easily, rounds fed and chambered smoothly, extraction and ejection was positive and consistent, and empty magazines ejected cleanly.

Lastly, we checked the weapon’s muzzle flash during a night fire under a full moon. It was quite noticeable with flame exiting the holes in the brake and a softball size ball of fire approximately 4 inches in front of the muzzle. Muzzle blast though was not bad and did not overly offend someone standing alongside the shooter.

Negatives? Past 150 yards the big, slow moving .50 caliber slug drops like a rock and is easily affected by wind. The magazine capacity of 7+1 rounds is limited. Ammunition is heavy, and expensive. The lack of an ejection port cover allows dirt and debris to enter the weapon’s action. An aggressive stance is needed for maximum control on rapid fire.

Positives? Any AR-15/M16 can be easily turned into a .50 Beowulf simply by switching uppers. The carbine is light, quick handling, and accurate. It operates exactly the same as any AR. While it “looks” like a 5.56x45mm AR it packs a short-range .50 caliber punch. The .50 Beowulf cartridge offers a substantial advantage over conventional 9x19mm, 5.56x45mm, and .308 weapons when engaging motor vehicles at short range. The design is refined, uses proven off-the-shelf parts for long service life, and is reliable.

Since I first evaluated the .50 Beowulf a year ago I’ve heard from several reliable sources about these weapons showing up in the most interesting places. It appears the .50 Beowulf has cleared all preliminary military testing and there are now units in the field with “U.S. approved personnel.” One of the great features of the basic AR system is that caliber swaps are easily made by simply changing upper receivers. So any 5.56x45mm AR can be instantly converted into a .50 Beowulf by simply pushing out two pins. For someone who may have to try to stop a motor vehicle the .50 Beowulf is a substantial step up from a MP5 or M4 carbine.

Currently Alexander Arms LLC is offering not only complete rifles but also upper receivers, ammunition, loading dies, and components as well. Price of the Precision rifle with one 7-round magazine and hard case, without optional extras, is $1,500.82. The .50 Beowulf is an interesting, and powerful cartridge. It shows just how versatile the basic AR-15/M16 platform truly is.


Alexander Arms LLC

U.S. Army Radford Arsenal
P.O. Box 1
Radford, VA 24143
Phone: 540-639-8356

Trijicon, Inc.
49385 Shafer Ave.
P.O. Box 930059
Wixom, MI 48393-0059
Phone: 248-960-7700
(Precision Tactical Optics)

Ace Ltd. USA
P.O. Box 191
Chicago Park, CA 95712
Phone: 530-346-2492
(Quality AR Accessories)

This article first appeared in Small Arms Review V6N10 (July 2003)
and was posted online on November 1, 2013


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