gunsnprices 0.1.0

Parse gun and ammo product titles: brand, model, caliber, magazine capacity, barrel length, rounds per box and cost per round. Pure Dart, no dependencies.

gunsnprices

Parse firearm and ammunition product titles into structured data: brand, model, caliber, magazine capacity, barrel length, rounds per box and cost per round.

import 'package:gunsnprices/gunsnprices.dart';

final info = parseTitle('Glock 19 Gen 5 MOS 9mm 4.02in 15rd Pistol PA195S203MOS');
info.model?.model;  // Glock 19 Gen 5 MOS
info.caliber?.name; // 9×19mm Parabellum
info.capacity;      // 15
info.barrelLength;  // 4.02

This is the title parser behind GunsNPrices, a price comparison site that tracks 40+ US gun and ammo stores. Store titles are messy (G19 GEN5 9MM 15RD FS, O/U 12/28 BL/WD 3", Federal 308 150gr ... 20rds), and matching the same product across stores starts with reading them reliably. The model dictionaries and the caliber list in this package are the ones the site uses to group listings, so you get the same model names you see on gunsnprices.com.

Pure Dart, null-safe, no dependencies. The data is compiled into the package as Dart constants, so it works in Flutter (mobile, desktop, web), in browsers and on the server. It is a port of the Python package and gives identical results: the test suite checks the same 1,150 recorded store titles as the Python and JavaScript versions (on the Dart VM and compiled to JavaScript), and it agrees with Python on all 63,755 titles of the GunsNPrices catalog.

Install

dart pub add gunsnprices
# or, in a Flutter app
flutter pub add gunsnprices

What it recognizes

Field	Example in a title	Result
Firearm or ammo	... 150gr ... 20rds	ProductKind.ammo
Brand and model (50 brands)	G19 Gen5 MOS, part number PA195S203	Glock 19 Gen 5 MOS
Calibers (293)	.357 Mag / .38 Spl, 6.5 CM, 12ga, 300 BLK, 7MM RM	.357 Mag, .38 S&W Special, ...
Magazine capacity	15+1, 17RD, 13rd/15rd, 10-shot	15, 17, 15, 10
Barrel length, inches	4.02in, 16 1/2", 22 BBL, O/U 12/28	4.02, 16.5, 22.0, 28.0
Rounds per box	50/Box, Box of 20, 1,000 Rounds, 20/25	50, 20, 1000, 20
Cost per round	price 449.99 + 1000 Rounds	0.45

Brands with model dictionaries: Barrett, Benelli, Beretta, Bergara, Browning, Cadex, Canik, Charles Daly, Chiappa, Christensen Arms, Cimarron, CMMG, Colt, CVA, CZ, Daniel Defense, Desert Eagle, Diamondback, Fierce, FN, Glock, Great Lakes, Henry, Heritage, HK, Howa, Kel-Tec, Kimber, Kriss, Marlin, Mossberg, Remington, Retay, Rossi, Ruger, Savage, SCCY, Seekins, Shadow Systems, Sig Sauer, Smith & Wesson, Springfield, Stevens, Stoeger, Taurus, Tikka, Tristar, Walther, Weatherby, Winchester.

Usage

Everything at once

final ammo = parseTitle(
  'Federal American Eagle 5.56x45mm 55gr FMJ 1000 Rounds',
  price: 449.99,
);
ammo.kind;          // ProductKind.ammo
ammo.caliber?.name; // 5.56×45mm NATO
ammo.rounds;        // 1000
ammo.costPerRound;  // 0.45

parseTitle(title, {brand, mpn, sku, price, kind}) returns a ProductInfo:

Field	Type	Notes
kind	ProductKind	firearm or ammo; pass kind to skip the guess
brand	String	brand of the identified model, else the brand you passed, else ''
model	ModelMatch?	firearms only
caliber	Caliber?	first caliber in the title
calibers	List<Caliber>	all calibers, in order
capacity	int?	magazine capacity (for 15+1 it is 15), firearms only
barrelLength	double?	inches, firearms only
rounds	int?	rounds per box, ammo only
costPerRound	double?	ammo with price only

toJson() gives a plain map with the same keys as the Python package (barrel_length, cost_per_round), so jsonEncode(info) works directly.

Passing brand (the manufacturer field from a feed) helps with titles that don't name the brand. Passing mpn lets it decode Glock part numbers when the title says nothing useful:

identifyModel('GLOCK 9MM PISTOL 15RD', brand: 'Glock', mpn: 'UA4350201')?.toJson();
// {brand: Glock, family: Glock 43, model: Glock 43, generation: , configs: [], features: [], source: mpn}

Models

final m = identifyModel('Sig Sauer P365 XL 9mm 3.7" 12+1 Optic Ready');
m?.family; // Sig Sauer P365
m?.model;  // Sig Sauer P365 XL

A ModelMatch has brand, family, model (the most specific name), generation, configs (such as MOS, Compact), features (such as Threaded Barrel, FDE) and source (ModelSource.title or ModelSource.mpn). Accessories, parts, airguns and airsoft are rejected, so it returns null for "Glock 19 holster" and "Umarex Glock 19 CO2 BB pistol".

Calibers

findCalibers('Henry Big Boy .44 Mag/.44 Spl 20in').map((c) => c.name);
// (.44 Magnum, .44 S&W Special)

normalizeCaliber('308 WIN (7.62X51 NATO)')?.toJson();
// {id: 308win, name: .308 Win, type: rifle, url: https://gunsnprices.com/ammo/rifle-ammo/308-win}

Each Caliber has a stable id, a display name, a type (CaliberType.handgun, rifle, rimfire, shotgun, airgun, muzzleloader) and the url of its GunsNPrices price comparison page. normalizeCaliber is meant for caliber fields in product feeds; findCalibers searches free text. listCalibers() returns all 293.

Numbers

magazineCapacity('Springfield Hellcat Pro OSP 9mm 3.7in 15rd/17rd'); // 17
barrelLength('Mossberg 590 Persuader 12/20 BL/SY 3"');              // 20.0 (3" is the chamber)
roundsPerBox('Winchester 308 150gr PowerMax Bonded 20rds');         // 20
costPerRound(31.99, 20);                                            // 1.5995

Command line

dart pub global activate gunsnprices
gunsnprices "Ruger GP100 .357 Mag / .38 Special 4.2in 6-shot Revolver"
cat titles.txt | gunsnprices > parsed.jsonl
gunsnprices --price 18.99 "Federal 9mm 115gr FMJ 50/Box"

Accuracy

Measured with the reference implementation on 50,202 firearm and 13,555 ammunition listings from 40+ stores on gunsnprices.com (October 2026), against the attributes stored on the site:

What	Found in the title	Right when found
Model (32,317 listings with a known model)	99.97%	99.8% same name as the site
Caliber, firearms	81%	97.8%
Caliber, ammo	91%	94.9%
Magazine capacity	46%	95.6%
Barrel length	58%	94.4%
Rounds per box	80%	96.6%

"Found" is limited by the titles themselves: many stores don't put the caliber or barrel length in the title at all. Most of the "wrong" cases we checked by hand are errors in the store data, not in the parser.

Data

The model dictionaries and caliber list ship inside the package (lib/src/data/, generated from the Python package's JSON by tool/generate_data.dart). The same data, with listing counts and price levels, is published as open datasets:

• Hugging Face: gunsnprices/firearm-calibers, gunsnprices/firearm-models
• GitHub: gunsnprices/firearm-datasets
• MCP server for AI assistants, built on the same parser: gunsnprices-mcp

Limitations

• Titles from US retailers, in English.
• Models are covered for the 50 brands above. Other brands still get calibers and numbers.
• Built for firearms and ammunition. Magazines, parts and accessories get calibers and numbers but no model.
• The first call builds the caliber index (about 0.2 s on the Dart VM); after that a title takes about 2 ms.

License

The code is under the MIT License. The model and caliber data in lib/src/data/ is under CC BY 4.0: you can use it for anything, including commercial use, if you credit GunsNPrices (gunsnprices.com) with a link.

Questions, corrections and missing models: open an issue or write to [e-mail]. Current gun and ammo prices: gunsnprices.com.