.50 Beowulf

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.50 Beowulf
Beowulf Cartridges.JPG
5.56 mm compared to .50 Beowulf cartridges.
Place of originUnited States
Production history
Parent case.50 Action Express
Case typeRebated rim, straight
Bullet diameter.500 in (12.7 mm)
Neck diameter.525 in (13.3 mm)
Base diameter.535 in (13.6 mm)
Rim diameter.445 in (11.3 mm)
Case length1.65 in (42 mm)
Overall length2.125 in (54.0 mm)
Primer typeLarge pistol magnum
Ballistic performance
Bullet mass/type Velocity Energy
300 gr (19 g) Speer Gold Dot JHP Alexander Arms 1,870 ft/s (570 m/s) 2,330 ft⋅lbf (3,160 J)
325 gr (21 g) Speer JHP Alexander Arms 1,800 ft/s (550 m/s) 2,338 ft⋅lbf (3,170 J)
335 gr (22 g) Rainer Plated FP Alexander Arms 1,771 ft/s (540 m/s) 2,333 ft⋅lbf (3,163 J)
335 gr (22 g) Rainier Plated HP Alexander Arms 1,900 ft/s (580 m/s) 2,678 ft⋅lbf (3,631 J)
400 gr (26 g) Hawk JFP Alexander Arms 1,800 ft/s (550 m/s) 2,878 ft⋅lbf (3,902 J)
Test barrel length: 16 inches
Source(s): [1]
.50 Beowulf AR-15

The .50 Beowulf is a 12mm caliber rifle cartridge developed by Bill Alexander of Alexander Arms for use in an AR-15 rifle.[1]

Design and specifications[edit]

The cartridge utilizes a rebated rim, sized to match the rim of the 6.5mm Grendel round. The case body is very similar in dimensions to the .500 S&W Magnum revolver cartridge, being slightly longer and fully tapered for automatic feeding in the weapon.

The round is intended to improve stopping power greatly at short- to medium-range as compared to the standard 5.56×45mm NATO round. One of its advertised uses is at vehicle checkpoints, since the heavy bullet's flight path is not easily deflected by auto glass or standard vehicle body panels.[citation needed]

Design limitations[edit]

With normal bullet weights between 300 and 400 grains (19 and 26 g), overall cartridge length shorter than that of an AR-15 magazine well, and holding to pressures of 33,000 psi limited by the AR bolt strength system,[2] the .50 Beowulf is best described as a low-velocity, heavy caliber, making its ballistics roughly equivalent to those of early .45-70 Government rounds rather than the higher pressure rounds tolerated by lever-action rifles such as the Marlin Model 1895.[3]

Proprietary status[edit]

The .50 Beowulf is a proprietary caliber developed as a specialized cartridge. Alexander Arms and Delta Firearms oversees all aspects of the production of the system and related accessories. Their reluctance to divulge information has been a source of irritation to some writers.[3] Because Alexander Arms holds a trademark on the name .50 Beowulf, a number of other companies produce weapons and ammunition reverse engineered to the same dimensions under the name 12.7x42mm.

Sporting uses[edit]

Although much has been written about its tactical uses, the .50 Beowulf is gaining recognition as a sporting cartridge. It is becoming more widely recognized as being usable for a wide variety of North American game,[4] including deer, moose, and black bear.[3]

Similar cartridges[edit]

The cartridge has its lineage in the .50 Action Express, starting with the L.A.R. Grizzly and in modern times, the Magnum Research Desert Eagle pistol, with significant modification to improve functionality and safety in the AR-15 rifle.[5]

See also[edit]


  1. ^ Berger, Matt (December 2011). "ALEXANDER ARMS .50 BEOWULF". Special weapons for military & police. Tactical-life.com. Retrieved March 26, 2019.
  2. ^ Cutshaw, Charlie (Jul–Aug 2006). ".50 caliber Beowulf". Tactical Response. Archived from the original on November 4, 2013. Retrieved January 28, 2013.
  3. ^ a b c D'Alessandro, Joseph. "The 50 Beowulf: A Reluctant Retrospective". Archived from the original on 2007-08-16. Retrieved 2009-06-22.
  4. ^ Youngblood, Paul (July 14, 2011). "What's the .50 Beowulf good for?". Guns & Ammo. Archived from the original on 2013-02-06. Retrieved January 28, 2013.
  5. ^ "Alexander Arms - Frequently Asked Questions". Archived from the original on 2012-01-04. Retrieved 2012-01-11.

External links[edit]