Alexander Arms .50 Beowulf
- Category
- Rifle
- Barrel
- 419 mm
- Weight, empty
- 3.65 kg
- Introduced
- 2001
About
What it is, and why it matters
The Alexander Arms .50 Beowulf is a heavy-caliber AR-15 platform rifle chambered in the proprietary .50 Beowulf (12.7x42mm) cartridge developed by Bill Alexander. It was designed to give the AR-15 platform vehicle-stopping power for checkpoint and short-range defensive use, delivering bullet weights between 200 and 600 grains at typical muzzle energies above 3,000 joules. The rifle uses a standard AR-15 lower receiver mated to a dedicated upper, modified bolt with rebated rim bolt face, and single-stack 7-round magazines that fit standard AR-15 magazine wells.
The .50 Beowulf was developed after September 11, 2001 specifically as a vehicle-stopping cartridge for AR-15 platforms manning U.S. checkpoints; Bill Alexander named it after the Old English epic, reasoning that a half-inch slug should have a hero's name. Hunters later discovered it would flatten anything from feral hogs to black bear inside 150 yards.
Cartridge name '50 Beowulf' is a registered trademark of Alexander Arms; the dimensionally identical metric designation 12.7x42mm is used by some other manufacturers to avoid the trademark. The rifle uses standard AR-15 buffers and springs.
Specification
Everything measured
IdentityWhat it is, who built it and when.
- Manufacturer
- Alexander Arms
- Category
- Rifle
- Country
- United States
- Status
- In production
- Produced
- 2001
DimensionsAs issued, without a magazine or an optic.
- Barrel
- 419 mm
- Overall length
- 920 mm
- Weight, empty
- 3.65 kg
ActionHow it cycles, what trips it, and what feeds it.
- Action
- Gas operated long stroke
- Firing mechanism
- Hammer fired
- Trigger
- Single stage
- Trigger pull
- 13.0 N
- Capacity
- 7
- Magazine
- Detachable box
MaterialsEach swatch is the material itself, not a colour chosen to stand for it.
- Frame
- Aluminum
- Barrel
- Steel
- Stock
- Polymer
- Finish
- Black anodized
BallisticsFrom the service cartridge, not a handload.
- Muzzle velocity
- 564 m/s
- Muzzle energy
- 3445 J
- Effective range
- 200 m
- Maximum range
- 1500 m
Trajectory
What the round does downrange
Solved from the muzzle figures and the bullet. The dashed rule is the effective range on the record, and the crosses are the steps the solver returned.
No load solved for this record yetThe flight path is computed from a cartridge and a bullet. This record has no ammunition filed against its chambering, so there is nothing to solve.
Features
What it has
What the record lists as fitted, drawn from the catalogue.
Ar15 platform compatible
Flat top upper
Picatinny rail
Adaptive tactical stock
Muzzle brake optional- Modified bolt face
Standing
How it compares
Each figure against the firearms of the same type and cartridge that record it, or of the same type where that cartridge has too few. Positions are read to the nearest tenth.
| Measurement | This firearm | Median | Position |
|---|---|---|---|
| Empty weightAmong 1,612 rifles | 3.65 kg | 3.50 kg | Heavier than about 60% |
| Overall lengthAmong 1,557 rifles | 920 mm | 1080 mm | Shorter than about 90% |
| Barrel lengthAmong 1,659 rifles | 419 mm | 584 mm | Shorter than about 90% |
| Magazine capacityAmong 1,611 rifles | 7 | 5 | Holds more rounds than about 60% |
Answers
Questions about the Alexander Arms .50 Beowulf
How much does the Alexander Arms .50 Beowulf weigh?
The Alexander Arms .50 Beowulf weighs 3.65 kg (8.05 lb) empty.
What caliber is the Alexander Arms .50 Beowulf?
The Alexander Arms .50 Beowulf is chambered in .50 Beowulf.
How many rounds does the Alexander Arms .50 Beowulf hold?
The Alexander Arms .50 Beowulf holds 7 rounds, fed from a detachable box magazine.
How long is the Alexander Arms .50 Beowulf?
The Alexander Arms .50 Beowulf is 920 mm (36.2 in) long overall, with a 419 mm (16.5 in) barrel.
Who makes the Alexander Arms .50 Beowulf?
The Alexander Arms .50 Beowulf is made by Alexander Arms (United States). It was designed by Bill Alexander.
When was the Alexander Arms .50 Beowulf introduced?
The Alexander Arms .50 Beowulf was introduced in 2001.
How does the Alexander Arms .50 Beowulf operate?
The Alexander Arms .50 Beowulf uses a gas operated long stroke action, and its firing mechanism is hammer fired.
Compatibility
Which parts fit this firearm
Studio
Every part that mounts on this, resolved
Not a list the maker typed out: the answer comes from the mounts this firearm exposes and the interface each part needs, so it stays right when either one changes.
- Every part that mounts on any firearm in the catalogue
- Interface standards, platforms and fit overrides
- The same answers through the API and the MCP server
Requires a signed-in GunSpec account on the Studio plan. The answer is computed per part, so it is not part of the public record.
Provenance
What the record holds
Every figure above was taken from one of these pages. The confidence reflects how much of the record came from a page a claim can be checked against.
In service
- United States civilian market
- 2001
Provenance
Confidence in this record
78%
Stockists
Where to buy
Offers link straight to the shop. GunSpec never takes the order.
No shop has listed this firearm yet
Stock and prices come from the shops themselves. If you sell this firearm, you can list it and it appears here.
List a firearmMCP
Ask an assistant about it
The same record, reached the way a person asks for it rather than the way a program does.
Ask GunSpec
Works with
Point an MCP client at GunSpec and it answers from the catalogue rather than from memory. A free key covers the read tools.
API
The call that returns this record
The same fields, in the same units, from the same endpoint the page reads.
curl --request GET \ --url 'https://api.gunspec.io/v1/firearms/alexander-arms-50-beowulf' \ --header 'X-API-Key: your_key'{ "id": "alexander-arms-50-beowulf", "name": "Alexander Arms .50 Beowulf", "manufacturer": { "id": "alexander-arms", "name": "Alexander Arms", "countryCode": "US", "foundedYear": 2001, "website": "https://www.alexanderarms.com", "logoUrl": null, "description": null, "status": null, "defunctYear": null, "stateOwned": null, "makesFirearms": null, "parentId": null, "predecessorId": null, "createdAt": "2026-04-05 22:24:37", "updatedAt": "2026-04-05 22:24:37", "version": "448f9289b6878e20e1cf58fdf2e7a371c9f2e11982c20f4c6ab29625efdb6e23" }, "category": { "id": "rifle", "name": "Rifle", "description": "Long-barreled firearms designed for accurate shooting" }, "country_of_origin": "US", "year_introduced": 2001, "barrel_length_mm": 419, "weight_empty_g": 3650, "action_type": "gas_operated_long_stroke"}