Get a caliber

Returns the full specification for a single cartridge.

Available on every plan. Requires an API key; Explorer keys receive a reduced field set.

get/v1/calibers/{id}

Request

Base URL: https://api.gunspec.io
URL: https://api.gunspec.io/v1/calibers/{id}
Auth: one of:
- API key in header X-API-Key
- HTTP bearer

Path parameters

idstring required

Caliber slug

Headers

If-None-Matchstring

The ETag from a previous response. If the body would be byte-identical, the API answers 304 Not Modified with no body. A 304 counts toward the per-minute rate limit but not the daily request allowance.

Response

Get a caliber

successboolean required

Always true on a successful response. Every error carries false and an error object instead.

Example response

{
  "success": true,
  "data": {
    "id": "9x19mm-parabellum",
    "name": "9x19mm Parabellum",
    "aliases": [
      "7.62x51mm NATO",
      ".308 Win"
    ],
    "natoDesignation": "9mm NATO",
    "bulletDiameterMm": 9.01,
    "neckDiameterMm": 9.65,
    "baseDiameterMm": 9.93,
    "rimDiameterMm": 9.96,
    "rimThicknessMm": 1.27,
    "caseLengthMm": 19.15,
    "overallLengthMm": 29.69,
    "bulletLengthMm": 15.5,
    "maxPressureMpa": 235,
    "maxPressurePsi": 34084,
    "typicalBulletWeightG": 7.45,
    "typicalMuzzleVelocityMps": 360,
    "typicalMuzzleEnergyJ": 481,
    "primerType": "small_pistol",
    "cartridgeType": "rimless",
    "caseShape": "tapered",
    "caseMaterial": "brass",
    "projectileKind": "bullet",
    "bulletProfile": "round_nose",
    "closure": "bullet",
    "yearIntroduced": 1902,
    "designer": "Georg Luger",
    "specSource": "https://en.wikipedia.org/wiki/9%C3%9719mm_Parabellum",
    "specStandard": "cip",
    "dataConfidence": 0.9,
    "verifiedAt": "2026-09-08",
    "verifiedFields": [
      "case_length_mm",
      "max_pressure_mpa"
    ],
    "createdAt": "2025-01-15 12:00:00",
    "updatedAt": "2026-09-10 06:42:19",
    "version": "a3f1c2d4e5b6a7c8d9e0f1a2b3c4d5e6f7a8b9c0d1e2f3a4b5c6d7e8f9a0b1c2",
    "provenance": {
      "sources": [
        "https://www.glock.com/en/products/pistols/g17-gen5"
      ],
      "sourceKinds": [
        {
          "url": "https://www.glock.com/en/products/pistols/g17-gen5",
          "kind": "manufacturer",
          "archivedFrom": null,
          "rank": 0,
          "tier": "authority",
          "basis": "declared",
          "evidence": null
        }
      ],
      "makerSource": "https://www.glock.com/en/products/pistols/g17-gen5",
      "evidence": "maker",
      "checks": {
        "raised": 3,
        "history": [
          {
            "task": "verify:firearms:glock-g17-gen5",
            "number": 1204,
            "check": "quality:firearm-weight-fits-its-size",
            "kind": "verify",
            "agent": "redback",
            "worker": "redback-046535",
            "status": "resolved",
            "decidedAt": "2026-09-25 07:42:39",
            "proposed": "Read https://us.glock.com/en/pistols/g17-gen5: agrees on barrel_length, weight.",
            "fields": [
              "barrel_length_mm",
              "weight_empty_g"
            ],
            "sources": [
              "https://us.glock.com/en/pistols/g17-gen5"
            ],
            "finding": {
              "why": "2.22 g/cm3 against a submachine-gun / carbon-steel median of 0.64; check the weight and the dimensions",
              "evidence": {
                "apparentDensity": 2.218,
                "categoryMedian": 0.635
              }
            }
          }
        ]
      },
      "dataConfidence": 0.95,
      "verifiedAt": "2026-09-08",
      "verifiedFields": [
        "barrel_length_mm",
        "weight_empty_g"
      ],
      "updatedAt": "2026-09-08 04:10:22",
      "version": "ba5c1d9e06c279a5"
    }
  }
}

Changes

No recorded changes to this operation across all 1 revision of this API.