GunSpec

All 44 examples

Tools

Free recoil

  1. 1

    A person asks

    • How much free recoil does an HK416 have against an M4 carbine firing M855?
  2. 2

    The assistant calls the tool

    tools/call
    json
    {  "name": "gunspec_firearm_recoil",  "arguments": {    "ids": [      "hk416",      "m4-carbine"    ],    "ammo_id": "m855"  }}
  3. 3

    The server answers

    Result
    json
    {  "method": {    "id": "saami-free-recoil",    "name": "SAAMI free recoil",    "equation": "I (N·s) = m_b·v + m_c·f·v; V (m/s) = I / M; E (J) = ½·M·V²; m_b the bullet and m_c the powder charge in kg, v the muzzle velocity from this barrel in m/s, f the gas velocity factor for the class of firearm, M the firearm in kg. Without a po…",    "citations": [      {        "authors": "Sporting Arms and Ammunition Manufacturers' Institute (SAAMI)",        "year": 2018,        "title": "Gun Recoil, Technical: Free Recoil Energy",        "journal": "SAAMI technical sheet, Rev. 7/9/2018",        "doi": null,        "url": "https://saami.org/wp-content/uploads/2025/03/Gun-Recoil-Formulae-2018-07-9.pdf"      },      {        "authors": "Hatcher JS",        "year": 1957,        "title": "Hatcher's Notebook, second edition, chapter The Theory of Recoil",        "journal": "The Military Service Publishing Company",        "doi": null,        "url": "https://archive.org/details/hatchers-notebook-by-julian-s.-hatcher"      }    ],    "gasFactors": {      "rifle": 1.75,      "shotgun": 1.5,      "shotgun_long_barrel": 1.25,      "handgun": 1.5    }  },  "shot": {    "mass": "loaded",    "powderChargeG": null,    "gasClass": null,    "lowerBound": true,    "defaulted": [      "mass",      "powder_charge_g",      "gas_class"    ]  },  "results": [    {      "firearm": {        "id": "hk416",        "name": "HK416",        "categoryId": "assault-rifle",        "barrelLengthMm": 264      },      "ammunition": {        "id": "m855",        "name": "M855 Ball (SS109)",        "caliberId": "5-56x45mm-nato",        "bulletWeightG": 4.02      },      "mass": {        "firearmG": 3420,        "basis": "loaded",        "source": "catalogue"      },      "muzzleVelocityMps": 777,      "gas": {        "class": "rifle",        "label": "High powered rifles",        "factor": 1.75,        "velocityMps": null,        "chargeG": null,        "classSource": "category"      },      "recoil": {        "impulseNs": 3.125,        "bulletImpulseNs": 3.125,        "gasImpulseNs": null,        "velocityMps": 0.914,        "energyJ": 1.43,        "lowerBound": true      },      "delta": null,      "warnings": [],      "error": null    },    {      "firearm": {        "id": "m4-carbine",        "name": "M4 Carbine",        "categoryId": "carbine",        "barrelLengthMm": 368      },      "ammunition": {        "id": "m855",        "name": "M855 Ball (SS109)",        "caliberId": "5-56x45mm-nato",        "bulletWeightG": 4.02      },      "mass": {        "firearmG": 3320,        "basis": "loaded",        "source": "catalogue"      },      "muzzleVelocityMps": 856,      "gas": {        "class": "rifle",        "label": "High powered rifles",        "factor": 1.75,        "velocityMps": null,        "chargeG": null,        "classSource": "category"      },      "recoil": {        "impulseNs": 3.442,        "bulletImpulseNs": 3.442,        "gasImpulseNs": null,        "velocityMps": 1.037,        "energyJ": 1.78,        "lowerBound": true      },      "delta": {        "energyJ": 0.36,        "velocityMps": 0.123,        "impulseNs": 0.316      },      "warnings": [],      "error": null    }  ]}

    Captured from the live API on Oct 22, 2026. Lists and long text are shortened for display.