FBP m/948
- Category
- Submachine Gun
- Barrel
- 249 mm
- Weight, empty
- 3.75 kg
- Introduced
- 1948
About
What it is, and why it matters
The FBP m/948 is a Portuguese 9x19mm submachine gun developed from a 1940 design by artillery officer Gonçalves Cardoso and put into production in 1948 by the state arsenal Fábrica de Braço de Prata in Lisbon. A simple blowback, open-bolt, full-automatic-only weapon, it combined the telescoping bolt and operating spring of the German MP40 with the stamped receiver layout and collapsible wire stock of the American M3 'Grease Gun'. Unusually for a submachine gun, it could mount the standard Portuguese Mauser bayonet, and it served as the primary Portuguese submachine gun through the early Colonial Wars in Angola and Mozambique.
The design was first conceived in 1940 by Major Gonçalves Cardoso of the Portuguese Army artillery, but its development was interrupted by the Second World War before it was finally completed and adopted in 1948.
Full-automatic fire only; the later m/963 variant added a selector for semi-automatic fire. Magazines were available in 21- and 32-round capacities.
Specification
Everything measured
IdentityWhat it is, who built it and when.
- Manufacturer
- Fábrica de Braço de Prata
- Category
- Submachine Gun
- Country
- Portugal
- Status
- Discontinued
- Produced
- 1948 to 1980
DimensionsAs issued, without a magazine or an optic.
- Barrel
- 249 mm
- Overall length
- 813 mm
- Weight, empty
- 3.75 kg
ActionHow it cycles, what trips it, and what feeds it.
- Action
- Blowback
- Firing mechanism
- Open bolt
- Capacity
- 32
- Magazine
- Detachable box
MaterialsEach swatch is the material itself, not a colour chosen to stand for it.
- Frame
- Steel
- Barrel
- Steel
- Stock
- Steel
- Finish
- Blued
BallisticsFrom the service cartridge, not a handload.
- Muzzle velocity
- 390 m/s
- Effective range
- 100 m
- Rate of fire
- 500 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.
Features
What it has
What the record lists as fitted, drawn from the catalogue.
Telescoping bolt
Collapsible wire stock
Stamped steel receiver
Bayonet lug
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 201 9x19mm Parabellum submachine guns | 3.75 kg | 3.18 kg | Heavier than about 80% |
| Overall lengthAmong 200 9x19mm Parabellum submachine guns | 813 mm | 723 mm | Longer than about 70% |
| Barrel lengthAmong 202 9x19mm Parabellum submachine guns | 249 mm | 213 mm | Longer than about 70% |
| Magazine capacityAmong 204 9x19mm Parabellum submachine guns | 32 | 32 | Holds more rounds than about 60% |
Answers
Questions about the FBP m/948
How much does the FBP m/948 weigh?
The FBP m/948 weighs 3.75 kg (8.27 lb) empty.
What caliber is the FBP m/948?
The FBP m/948 is chambered in 9x19mm Parabellum.
How many rounds does the FBP m/948 hold?
The FBP m/948 holds 32 rounds, fed from a detachable box magazine.
How long is the FBP m/948?
The FBP m/948 is 813 mm (32.0 in) long overall, with a 249 mm (9.80 in) barrel.
Who makes the FBP m/948?
The FBP m/948 is made by Fábrica de Braço de Prata (Portugal). It was designed by Gonçalves Cardoso.
When was the FBP m/948 introduced?
The FBP m/948 was introduced in 1948 and discontinued in 1980.
How does the FBP m/948 operate?
The FBP m/948 uses a blowback action, and its firing mechanism is open bolt.
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
- Portuguese Armed Forces
- 1948
- Mozambique
- Mozambique
- Angola
- Angola
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/fbp-m-948' \ --header 'X-API-Key: your_key'{ "id": "fbp-m-948", "name": "FBP m/948", "manufacturer": { "id": "fabrica-de-braco-de-prata", "name": "Fábrica de Braço de Prata", "countryCode": "PT", "foundedYear": 1908, "website": null, "logoUrl": null, "description": null, "status": null, "defunctYear": null, "stateOwned": null, "makesFirearms": null, "parentId": null, "predecessorId": null, "createdAt": "2026-06-21 23:00:46", "updatedAt": "2026-06-21 23:00:46", "version": "3d2bd9736689ecd205de4c12f4a1a2361492dc6c39af79fd01d6037af44bc752" }, "category": { "id": "submachine-gun", "name": "Submachine Gun", "description": "Automatic firearms chambered in pistol calibers" }, "country_of_origin": "PT", "year_introduced": 1948, "barrel_length_mm": 249, "weight_empty_g": 3750, "action_type": "blowback"}