{
 "version": "2026-10-20",
 "license": "Dimension sheets: CC BY 4.0. Standard and published-size files: CC BY 4.0. Xem Studio's own designs (files_license = Xem Studio Design License): free to use and sell things from, not to redistribute as files — https://xemstudio.com/license/. Other publishers' files: their own license, linked beside them.",
 "slug": "scope-dovetail-rails",
 "name": "Scope dovetail rails: 11 mm (European) and 3/8 in (US), and Weaver",
 "kind": "standard",
 "category": "Hardware",
 "group": "Mounting standards",
 "year": null,
 "question": "What are 11 mm and 3/8 in dovetail and Weaver rail dimensions?",
 "tags": [
  "rail",
  "mount",
  "dovetail",
  "scope mount",
  "airgun",
  "weaver"
 ],
 "aliases": [
  "11mm dovetail rail dimensions",
  "3/8 dovetail rail",
  "airgun scope rail",
  "weaver rail dimensions",
  "rimfire dovetail",
  "11mm vs 3/8 dovetail"
 ],
 "overall_mm": {
  "length": null,
  "width": null,
  "height": null
 },
 "official_cad": false,
 "xem_status": "not-scanned",
 "les": false,
 "free_files": 0,
 "url": "https://xemstudio.com/objects/scope-dovetail-rails/",
 "sheet_txt": "https://xemstudio.com/objects/scope-dovetail-rails/sheet.txt",
 "sheet": {
  "basis": "Published dimensions only (Optics Trade technical article; Brownells GunTech via AccurateShooter); groove depth and height are not standardized, so no file",
  "overall_mm": {
   "length": null,
   "width": null,
   "height": null
  },
  "notes": [
   "Airguns, rimfire rifles and many airsoft and crossbow scopes use a plain dovetail instead of Picatinny.",
   "11 mm dovetail: 11 mm across the top with 60° sides (the European standard). 3/8 in dovetail: 12.7 mm across the top with 45° sides (the US standard); the 3/8 in is measured across the bottom. Their depths and heights vary by maker, so Xem publishes no file: measure your rail's height before designing a clamp.",
   "Weaver: grooves .180 in wide, with no standard centre-to-centre spacing.",
   "Picatinny (MIL-STD-1913) is fully specified: see its page for the complete profile and files."
  ],
  "table": {
   "columns": [
    "rail",
    "top width",
    "side angle",
    "groove"
   ],
   "rows": [
    [
     "11 mm dovetail",
     "11 mm",
     "60°",
     "none"
    ],
    [
     "3/8 in dovetail",
     "12.7 mm (3/8 in across the bottom)",
     "45°",
     "none"
    ],
    [
     "Weaver",
     "not standardized",
     "—",
     ".180 in wide, spacing not standardized"
    ]
   ]
  }
 },
 "sheet_text": "Scope dovetail rails: 11 mm (European) and 3/8 in (US), and Weaver — dimension sheet\nSource: Xem Studio, https://xemstudio.com/objects/scope-dovetail-rails/  (sheet CC BY 4.0)\nBasis: Published dimensions only (Optics Trade technical article; Brownells GunTech via AccurateShooter); groove depth and height are not standardized, so no file\nCatalog version: 2026-10-20\n\nSizes: see table below\n- Airguns, rimfire rifles and many airsoft and crossbow scopes use a plain dovetail instead of Picatinny.\n- 11 mm dovetail: 11 mm across the top with 60° sides (the European standard). 3/8 in dovetail: 12.7 mm across the top with 45° sides (the US standard); the 3/8 in is measured across the bottom. Their depths and heights vary by maker, so Xem publishes no file: measure your rail's height before designing a clamp.\n- Weaver: grooves .180 in wide, with no standard centre-to-centre spacing.\n- Picatinny (MIL-STD-1913) is fully specified: see its page for the complete profile and files.\n\nrail  top width  side angle  groove\n11 mm dovetail  11 mm  60°  none\n3/8 in dovetail  12.7 mm (3/8 in across the bottom)  45°  none\nWeaver  not standardized  —  .180 in wide, spacing not standardized\n\nFiles elsewhere (not hosted by Xem Studio; license as stated by the publisher):\n- Optics Trade: 11 mm and 3/8\" dovetails — web — Publisher's page; dimensions are facts — https://www.optics-trade.eu/blog/11-mm-and-3-8-dovetails/\n- AccurateShooter (Brownells GunTech): Picatinny vs. Weaver rail specifications — web — Publisher's page; dimensions are facts — https://bulletin.accurateshooter.com/?p=5211\n\nNo true-size file yet: the published figures do not fix the whole shape; a measured scan is planned.\nAPI: https://xemstudio.com/api/geometry?object=scope-dovetail-rails\n",
 "sources": [
  {
   "publisher": "Optics Trade",
   "title": "11 mm and 3/8\" dovetails",
   "url": "https://www.optics-trade.eu/blog/11-mm-and-3-8-dovetails/",
   "formats": [
    "web"
   ],
   "license": "Publisher's page; dimensions are facts",
   "license_verified": true,
   "hosted": false
  },
  {
   "publisher": "AccurateShooter (Brownells GunTech)",
   "title": "Picatinny vs. Weaver rail specifications",
   "url": "https://bulletin.accurateshooter.com/?p=5211",
   "formats": [
    "web"
   ],
   "license": "Publisher's page; dimensions are facts",
   "license_verified": true,
   "hosted": false
  }
 ],
 "xem": {
  "status": "not-scanned",
  "sheet_free": true,
  "mesh_price_usd": null,
  "step_price_usd": null,
  "tolerance_mm": null
 },
 "related": [
  "picatinny-rail-mil-std-1913",
  "dovetail-rail-mount"
 ],
 "fits": [],
 "dimensions": "exact (nominal, no printing tolerance)",
 "dimension_rule": "All geometry on Xem Studio is exact (nominal, true size) with no printing tolerance. Where a part meets another part, the object lists its mating features (feature, exact size, what it mates with, fit class: press, slide, run, socket, clamp or designed). Apply your process's allowance to those features only; 'designed' gaps are part of the design and stay as drawn.",
 "mating": [],
 "faq": [
  {
   "q": "Are 11 mm and 3/8 in dovetails interchangeable?",
   "a": "Not with ordinary mounts: 11 mm is 11 mm wide at 60°, 3/8 in is 12.7 mm at 45°; some mounts with reversible clamps fit both."
  }
 ],
 "files_license": null,
 "offers": [],
 "markdown": "https://xemstudio.com/objects/scope-dovetail-rails/index.md"
}