Johnson M1941 LMG
- Category
- Machine Gun
- Barrel
- 560 mm
- Weight, empty
- 5.90 kg
- Introduced
- 1941
About
What it is, and why it matters
The Johnson M1941 LMG is an American short-recoil-operated light machine gun chambered in .30-06 Springfield, designed by Melvin Johnson in the late 1930s. Exceptionally light for its class at around 5.9 kg, it fed from a distinctive single-stack 20-round box magazine mounted on the left side and fired single shots from a closed bolt for accuracy while delivering automatic fire from an open bolt. Its quick-change barrel and adjustable cyclic rate made it a flexible squad support weapon, and it saw limited but notable service with US Marine Raiders, the First Special Service Force (the 'Devil's Brigade'), and Allied forces during World War II.
Melvin Johnson, a Boston lawyer and USMC reservist, developed the M1941 LMG alongside his recoil-operated rifle as a private venture to compete with the Browning Automatic Rifle. Though never formally adopted by the US Army, it became a favored weapon of the elite First Special Service Force, the 'Devil's Brigade.'
Manufactured by the Cranston Arms Company of Providence, Rhode Island. Magazine capacity is most commonly cited as 20 rounds (single-stack, left-side feed), though some sources list 25. The dual closed-bolt/open-bolt firing cycle was unusual for a machine gun of the era.
Specification
Everything measured
IdentityWhat it is, who built it and when.
- Manufacturer
- Johnson Automatics, Inc.
- Category
- Machine Gun
- Country
- United States
- Status
- Discontinued
- Produced
- 1941 to 1945
DimensionsAs issued, without a magazine or an optic.
- Barrel
- 560 mm
- Overall length
- 1100 mm
- Weight, empty
- 5.90 kg
ActionHow it cycles, what trips it, and what feeds it.
- Action
- Short recoil
- Firing mechanism
- Hammer fired
- Trigger
- Single action
- Capacity
- 20
- Magazine
- Detachable box
MaterialsEach swatch is the material itself, not a colour chosen to stand for it.
- Frame
- Steel
- Barrel
- Steel
- Stock
- Wood
- Finish
- Blued
BallisticsFrom the service cartridge, not a handload.
- Muzzle velocity
- 853 m/s
- Muzzle energy
- 4243 J
- Effective range
- 550 m
- Maximum range
- 3200 m
- Rate of fire
- 600 rpm
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.
Quick change barrel
Selective fire
Single shot closed bolt
Full auto open bolt- Adjustable rate of fire
Side mounted magazine
Bipod
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 261 machine guns | 5.90 kg | 10.50 kg | Lighter than about 90% |
| Overall lengthAmong 260 machine guns | 1100 mm | 1156 mm | Shorter than about 60% |
| Barrel lengthAmong 257 machine guns | 560 mm | 605 mm | Shorter than about 70% |
| Magazine capacityAmong 222 machine guns | 20 | 50 | Holds fewer rounds than about 90% |
Answers
Questions about the Johnson M1941 LMG
How much does the Johnson M1941 LMG weigh?
The Johnson M1941 LMG weighs 5.90 kg (13.01 lb) empty.
What caliber is the Johnson M1941 LMG?
The Johnson M1941 LMG is chambered in .30-06 Springfield.
How many rounds does the Johnson M1941 LMG hold?
The Johnson M1941 LMG holds 20 rounds, fed from a detachable box magazine.
How long is the Johnson M1941 LMG?
The Johnson M1941 LMG is 1100 mm (43.3 in) long overall, with a 560 mm (22.0 in) barrel.
Who makes the Johnson M1941 LMG?
The Johnson M1941 LMG is made by Johnson Automatics, Inc. (United States). It was designed by Melvin Johnson.
When was the Johnson M1941 LMG introduced?
The Johnson M1941 LMG was introduced in 1941 and discontinued in 1945.
How does the Johnson M1941 LMG operate?
The Johnson M1941 LMG uses a short recoil 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 Marine Corps
- 1942
- First Special Service Force
- 1942
- Royal Netherlands East Indies Army
- Netherlands
- Canadian Army
- Canada
- Philippine Commonwealth Army
- Philippines
Provenance
Confidence in this record
82%
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/johnson-lmg' \ --header 'X-API-Key: your_key'{ "id": "johnson-lmg", "name": "Johnson M1941 LMG", "manufacturer": { "id": "johnson-automatics", "name": "Johnson Automatics, Inc.", "countryCode": "US", "foundedYear": 1939, "website": null, "logoUrl": null, "description": null, "status": null, "defunctYear": null, "stateOwned": null, "makesFirearms": null, "parentId": null, "predecessorId": null, "createdAt": "2026-04-26 23:12:00", "updatedAt": "2026-04-26 23:12:00", "version": "387fe2c48d6cd35b5478b19cfa6ad6485c12a71075bf64e0a67e3872a7a3b1db" }, "category": { "id": "machine-gun", "name": "Machine Gun", "description": "Fully automatic firearms for sustained fire" }, "country_of_origin": "US", "year_introduced": 1941, "barrel_length_mm": 560, "weight_empty_g": 5900, "action_type": "short_recoil"}