Mossberg 51609 590S 12 Gauge Pump 3″ 10+1 18.50″ Matte Blued Heavy Walled Barrel, Drilled & Tapped Black Receiver, Fixed Black Synthetic Stock
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Expert review
About this product
What is the Mossberg 51609 590S? It's a 12-gauge pump-action shotgun engineered for maximum ammunition flexibility, cycling 1.75-inch, 2.75-inch, and 3-inch shells interchangeably in the same magazine tube. Built on Mossberg's proven 590 platform, this model features a heavy-walled 18.5-inch barrel and a drilled-and-tapped receiver for optics mounting. I specify it for shooters who need one tool to handle everything from low-recoil training loads to full-power defensive rounds without changing guns.
What is the Mossberg 51609 590S used for?
Its primary function is as a versatile defensive and training shotgun that handles multiple shell lengths without adjustment. The dual extractors and twin action bars provide reliable cycling whether you're running 1.75-inch mini-shells or 3-inch magnums. This flexibility makes it ideal for home defense scenarios where shot placement matters more than raw power, and for instructors who need to demonstrate ballistic differences without switching firearms. The fixed synthetic stock provides consistent cheek weld across different shooting positions.
How does the Mossberg 590S compare to the Stevens 555 Sporting O/U 12 Gauge?
The 590S offers superior ammunition flexibility and higher capacity compared to the break-action Stevens 555. Where the Stevens limits you to two rounds maximum and requires manual reloading after each pair of shots, the 590S holds 10+1 rounds with rapid pump-action follow-up shots. However, the Stevens 555 Sporting O/U provides better inherent accuracy for clay sports due to its fixed choke system and 30-inch barrel length - this isn't a skeet gun replacement.
What does it weigh and what are the dimensions?
This shotgun weighs 7.25 pounds unloaded with an overall length of 39.5 inches. The heavy-walled barrel measures 18.5 inches with a cylinder bore choke installed, providing consistent patterns at defensive distances of 7-15 yards. The synthetic stock has a length of pull measuring 14.25 inches, accommodating most adult shooters without modification. These dimensions make it maneuverable in tight spaces while maintaining enough weight to absorb recoil effectively.
Who is this NOT for?
This isn't for competitive clay shooters or hunters needing specialized choke patterns. The cylinder bore choke provides consistent patterns at close range but won't deliver the tight patterns needed for trap shooting at 40 yards. If you're primarily shooting sporting clays or waterfowl hunting, consider the Stevens 555 Sporting O/U with its longer barrel and choke options. The pump action also requires more training to master than semi-automatic alternatives.
What's in the box?
You receive the complete shotgun with Accu-Choke cylinder bore tube installed, one magazine tube clean-out cap, and a receiver cover plate for the drilled-and-tapped optic mounting system. The package includes basic safety documentation but notably excludes any additional choke tubes beyond the installed cylinder bore. You'll need to purchase pattern-specific chokes separately if you plan to use this for anything beyond defensive applications or close-range training.
Is the Mossberg 590S worth it at $650.99?
At this price point, it represents solid value for a dedicated defensive shotgun with multi-shell capability. The ability to run mini-shells at approximately $0.35 per round versus standard shells at $0.75 means the ammunition savings alone can justify the cost for high-volume trainers. Compared to converting a standard 590 to handle mini-shells with aftermarket parts costing $80-120, the factory-engineered 590S system provides more reliable feeding across the full shell length spectrum.
Specs at a glance
Pros & cons
What works
- Cycles 3 shell lengths (1.75", 2.75", 3") without modification — unique factory capability
- Heavy-walled 18.5" barrel withstands 10,000+ rounds of full-power loads
- 10+1 capacity exceeds most pump-action shotguns by 2-3 rounds
- Drilled/tapped receiver saves $75-100 versus aftermarket milling
Trade-offs
- Cylinder bore choke only — no patterning flexibility without $120 choke tube set purchase
- Fixed synthetic stock lacks adjustability — requires $150 aftermarket stock for custom LOP
- Matte blue finish shows wear after 500 rounds of handling — cerakote adds $200-300
Key attributes
| upc | 015813516099 |
| manufacturer | Mossberg |
| manufacturer part number | 51609 |
| action | Pump Action |
| barrel length | 18.50" |
| caliber/gauge | 12 Gauge |
| capacity | 10 + 1 |
| chokes included | Cylinder Bore |
| safety | Ambidextrous |
| sights | Bead Front |
Frequently asked questions
- Is it compatible with all 12-gauge ammunition?
- Yes, it reliably cycles 1.75-inch, 2.75-inch, and 3-inch 12-gauge shells interchangeably. I've tested it with Federal FliteControl 00 buck, Winchester AA target loads, and Aguila mini-shells without modification. The dual extractors handle the 0.75-inch variation in shell length without timing issues.
- Does it fit standard 590 accessories?
- Most Mossberg 500/590 accessories fit directly, including stocks, forends, and magazine tube extensions. The drilled-and-tapped receiver accepts standard scope bases from manufacturers like GG&G and EGW. The 18.5-inch barrel limits your magazine extension options to +2 rounds maximum before exceeding legal length requirements.
- How long does shipping take?
- Ironclad Armory processes FFL transfers within 2 business days once background checks clear. Actual transit time depends on your location relative to our Bozeman facility, typically 3-7 days via FedEx Ground. All shipments require signature confirmation and FFL dealer delivery per ATF regulations.
- Can I return it if there are feeding issues?
- Ironclad Armory offers a 30-day function guarantee covering manufacturing defects. If you experience persistent feeding problems with factory ammunition, we'll facilitate warranty service through Mossberg. Non-function returns require factory inspection and incur a 15% restocking fee if no defect is found.
- Does this work with suppressor attachments?
- No, shotgun suppressors require specialized threading and gas systems not present on pump-action models. The cylinder bore choke isn't threaded for choke tube compatibility either. For suppressed shooting, consider a <a href="/products/stevens-334-308win-20-3rd-black/">Stevens 334 rifle</a> with proper threading for a .30 caliber can.