Mossberg 500 Mariner
- Category
- Shotgun
- Barrel
- 470 mm
- Weight, empty
- 3.06 kg
- Introduced
- 1989
About
What it is, and why it matters
The Mossberg 500 Mariner is a corrosion-resistant marine variant of the Mossberg 500 pump-action shotgun, chambered in 12 gauge with a 3-inch chamber. It wears Mossberg's proprietary Marinecote metal finish, an electroless nickel and Teflon coating that Mossberg states resists corrosion better than stainless steel, making the shotgun well suited to boats, coastal patrol, and other harsh saltwater environments. It retains the 500 platform's aluminum receiver, twin action bars, dual extractors, tang-mounted safety, and 18.5-inch cylinder-bore barrel with a bead front sight.
The Marinecote finish was developed to give the workhorse Mossberg 500 a fighting chance against the constant salt spray of marine duty, where standard blued steel would rust within days.
Offered in full-stock and pistol-grip configurations; the JIC (Just In Case) Mariner packs a pistol-grip shotgun into a sealable survival tube. Capacity is typically 6 rounds (5+1) with 2.75-inch shells.
Specification
Everything measured
IdentityWhat it is, who built it and when.
- Manufacturer
- O.F. Mossberg & Sons
- Category
- Shotgun
- Country
- United States
- Status
- In production
- Produced
- 1989
- Variant of
- Marine corrosion resistant
DimensionsAs issued, without a magazine or an optic.
- Barrel
- 470 mm
- Overall length
- 1003 mm
- Weight, empty
- 3.06 kg
ActionHow it cycles, what trips it, and what feeds it.
- Action
- Pump action
- Firing mechanism
- Hammer fired
- Capacity
- 6
- Magazine
- Tubular
MaterialsEach swatch is the material itself, not a colour chosen to stand for it.
- Frame
- Aluminum alloy
- Barrel
- Steel
- Stock
- Synthetic
- Finish
- Marinecote
BallisticsFrom the service cartridge, not a handload.
- Muzzle velocity
- 400 m/s
- Effective range
- 40 m
Trajectory
What the round does downrange
Solved from the muzzle figures and the bullet. The dashed rule is the effective range on the record, and the crosses are the steps the solver returned.
No load solved for this record yetThe flight path is computed from a cartridge and a bullet. This record has no ammunition filed against its chambering, so there is nothing to solve.
Features
What it has
What the record lists as fitted, drawn from the catalogue.
Corrosion resistant marinecote finish
Dual extractors
Twin action bars
Anti jam elevator
3 inch chamber
Bead front sight
Interchangeable barrels
Standing
How it compares
Each figure against the firearms of the same type and cartridge that record it, or of the same type where that cartridge has too few. Positions are read to the nearest tenth.
| Measurement | This firearm | Median | Position |
|---|---|---|---|
| Empty weightAmong 622 12 Gauge shotguns | 3.06 kg | 3.29 kg | Lighter than about 80% |
| Overall lengthAmong 570 12 Gauge shotguns | 1003 mm | 1150 mm | Shorter than about 80% |
| Barrel lengthAmong 650 12 Gauge shotguns | 470 mm | 711 mm | Shorter than about 90% |
| Magazine capacityAmong 647 12 Gauge shotguns | 6 | 3 | Holds more rounds than about 90% |
Answers
Questions about the Mossberg 500 Mariner
How much does the Mossberg 500 Mariner weigh?
The Mossberg 500 Mariner weighs 3.06 kg (6.75 lb) empty.
What caliber is the Mossberg 500 Mariner?
The Mossberg 500 Mariner is chambered in 12 Gauge.
How many rounds does the Mossberg 500 Mariner hold?
The Mossberg 500 Mariner holds 6 rounds, fed from a tubular magazine.
How long is the Mossberg 500 Mariner?
The Mossberg 500 Mariner is 1003 mm (39.5 in) long overall, with a 470 mm (18.5 in) barrel.
Who makes the Mossberg 500 Mariner?
The Mossberg 500 Mariner is made by O.F. Mossberg & Sons (United States). It was designed by Carl Benson.
When was the Mossberg 500 Mariner introduced?
The Mossberg 500 Mariner was introduced in 1989.
How does the Mossberg 500 Mariner operate?
The Mossberg 500 Mariner uses a pump action, and its firing mechanism is hammer fired.
Compatibility
Which parts fit this firearm
Studio
Every part that mounts on this, resolved
Not a list the maker typed out: the answer comes from the mounts this firearm exposes and the interface each part needs, so it stays right when either one changes.
- Every part that mounts on any firearm in the catalogue
- Interface standards, platforms and fit overrides
- The same answers through the API and the MCP server
Requires a signed-in GunSpec account on the Studio plan. The answer is computed per part, so it is not part of the public record.
Provenance
What the record holds
Every figure above was taken from one of these pages. The confidence reflects how much of the record came from a page a claim can be checked against.
In service
- United States Coast Guard
- United States
Provenance
Confidence in this record
80%
Stockists
Where to buy
Offers link straight to the shop. GunSpec never takes the order.
No shop has listed this firearm yet
Stock and prices come from the shops themselves. If you sell this firearm, you can list it and it appears here.
List a firearmMCP
Ask an assistant about it
The same record, reached the way a person asks for it rather than the way a program does.
Ask GunSpec
Works with
Point an MCP client at GunSpec and it answers from the catalogue rather than from memory. A free key covers the read tools.
API
The call that returns this record
The same fields, in the same units, from the same endpoint the page reads.
curl --request GET \ --url 'https://api.gunspec.io/v1/firearms/mossberg-500-mariner' \ --header 'X-API-Key: your_key'{ "id": "mossberg-500-mariner", "name": "Mossberg 500 Mariner", "manufacturer": { "id": "mossberg", "name": "O.F. Mossberg & Sons", "countryCode": "US", "foundedYear": 1919, "website": "https://www.mossberg.com", "logoUrl": null, "description": null, "status": null, "defunctYear": null, "stateOwned": null, "makesFirearms": null, "parentId": null, "predecessorId": null, "createdAt": "2026-02-11 23:44:40", "updatedAt": "2026-02-18 03:40:45", "version": "efbce48d45f2bf96c91e5b66c03052b97d55affea9178a31feda8fd7fc882671" }, "category": { "id": "shotgun", "name": "Shotgun", "description": "Smoothbore firearms designed to fire shot or slugs" }, "country_of_origin": "US", "year_introduced": 1989, "barrel_length_mm": 470, "weight_empty_g": 3062, "action_type": "pump_action"}