Maschinenkarabiner MKb 42(W)
- Category
- Assault Rifle
- Barrel
- 401 mm
- Weight, empty
- 4.40 kg
- Introduced
- 1942
About
What it is, and why it matters
The Maschinenkarabiner MKb 42(W) was Carl Walther's select-fire assault rifle, one of the two competing prototypes that pioneered the intermediate-cartridge assault-rifle concept for the German Wehrmacht in 1942. Chambered for the 7.92x33mm Kurz round and feeding from a 30-round detachable box magazine, it was gas operated with an unusual annular gas piston encircling the barrel beneath stamped sheet-metal handguards. Unlike the rival Haenel MKb 42(H), the Walther fired from a closed bolt through a hammer-fired trigger and locked with a rotating bolt bearing two lugs, which gave it superior single-shot accuracy but a more complicated, less reliable action. Only around 200 were built before the design lost the trials to the Haenel weapon, which was developed onward into the MP 43 and StG 44.
Because Hitler had forbidden development of a new-caliber carbine, the Wehrmacht ran the program under the innocuous label Maschinenkarabiner ('machine carbine'), pitting Walther's closed-bolt MKb 42(W) against Haenel's open-bolt MKb 42(H). The Walther was the more accurate single-shot performer, but its intricate rotating bolt and annular gas piston proved fussier in the field, and the simpler Haenel won the contest that ultimately gave rise to the Sturmgewehr.
The (W) suffix denotes Walther, distinguishing it from the competing Haenel MKb 42(H). Sources vary on dimensions: empty weight is quoted between roughly 4.4 and 4.95 kg, overall length 931-944 mm, barrel 400-409 mm, and cyclic rate 500-600 rpm. Production was cancelled in November 1942 after about 200 units.
Specification
Everything measured
IdentityWhat it is, who built it and when.
- Manufacturer
- Carl Walther GmbH
- Category
- Assault Rifle
- Country
- Germany
- Status
- Limited production
- Produced
- 1942 to 1942
DimensionsAs issued, without a magazine or an optic.
- Barrel
- 401 mm
- Overall length
- 940 mm
- Weight, empty
- 4.40 kg
- Weight, loaded
- 4.99 kg
ActionHow it cycles, what trips it, and what feeds it.
- Action
- Gas operated long stroke
- Firing mechanism
- Hammer fired
- Trigger
- Single stage
- Capacity
- 30
- Magazine
- Detachable box
MaterialsEach swatch is the material itself, not a colour chosen to stand for it.
- Frame
- Steel
- Slide
- Steel
- Barrel
- Steel
- Stock
- Wood
- Finish
- Blued
BallisticsFrom the service cartridge, not a handload.
- Muzzle velocity
- 650 m/s
- Muzzle energy
- 1710 J
- Effective range
- 600 m
- Maximum range
- 800 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.
Selective fire
Rotating bolt
Closed bolt operation
Annular gas piston
Stamped sheet metal receiver
Left side charging handle
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 274 assault rifles | 4.40 kg | 3.59 kg | Heavier than about 90% |
| Overall lengthAmong 271 assault rifles | 940 mm | 915 mm | Longer than about 60% |
| Barrel lengthAmong 271 assault rifles | 401 mm | 415 mm | Shorter than about 70% |
| Magazine capacityAmong 276 assault rifles | 30 | 30 | Holds more rounds than about 60% |
Answers
Questions about the Maschinenkarabiner MKb 42(W)
How much does the Maschinenkarabiner MKb 42(W) weigh?
The Maschinenkarabiner MKb 42(W) weighs 4.40 kg (9.70 lb) empty and 4.99 kg (11.00 lb) loaded.
What caliber is the Maschinenkarabiner MKb 42(W)?
The Maschinenkarabiner MKb 42(W) is chambered in 7.92x33mm Kurz.
How many rounds does the Maschinenkarabiner MKb 42(W) hold?
The Maschinenkarabiner MKb 42(W) holds 30 rounds, fed from a detachable box magazine.
How long is the Maschinenkarabiner MKb 42(W)?
The Maschinenkarabiner MKb 42(W) is 940 mm (37.0 in) long overall, with a 401 mm (15.8 in) barrel.
Who makes the Maschinenkarabiner MKb 42(W)?
The Maschinenkarabiner MKb 42(W) is made by Carl Walther GmbH (Germany). It was designed by Carl Walther GmbH design team.
When was the Maschinenkarabiner MKb 42(W) introduced?
The Maschinenkarabiner MKb 42(W) was introduced in 1942 and discontinued in 1942.
How does the Maschinenkarabiner MKb 42(W) operate?
The Maschinenkarabiner MKb 42(W) 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
- Wehrmacht
- 1942
Provenance
Confidence in this record
68%
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/mkb-42-w' \ --header 'X-API-Key: your_key'{ "id": "mkb-42-w", "name": "Maschinenkarabiner MKb 42(W)", "manufacturer": { "id": "walther", "name": "Carl Walther GmbH", "countryCode": "DE", "foundedYear": 1886, "website": "https://www.carl-walther.de", "logoUrl": null, "description": "German manufacturer of sporting, competition, and defense firearms. Founded in 1886, Carl Walther is known for precision weapons technology.", "status": null, "defunctYear": null, "stateOwned": null, "makesFirearms": null, "parentId": null, "predecessorId": null, "createdAt": "2026-02-11 23:44:40", "updatedAt": "2026-02-18 03:40:48", "version": "d65d37557d49efec8a72ef6019ef9e5cab9430c505d88b909eaad72b3bf3cfb3" }, "category": { "id": "assault-rifle", "name": "Assault Rifle", "description": "Selective-fire rifles chambered in intermediate cartridges" }, "country_of_origin": "DE", "year_introduced": 1942, "barrel_length_mm": 401, "weight_empty_g": 4400, "action_type": "gas_operated_long_stroke"}