List calibers

Returns a paginated list of cartridges with their dimensional specifications.

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

get/v1/calibers

Request

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

Query parameters

pageinteger

Page number, from 1 to 10,000

per_pageinteger

Items per page (max 100)

qstring

Substring match on caliber name or alias

cartridge_typestring

Filter by cartridge type

primer_typestring

Filter by primer type

action_typestring

Only cartridges chambered by at least one firearm with this action, as stored and underscored. The vocabulary is /v1/firearms/action-types

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

List calibers

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"
      }
    }
  ],
  "pagination": {
    "page": 1,
    "per_page": 20,
    "limit": 20,
    "total": 42,
    "totalPages": 3
  }
}

Changes

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