Mossberg 590A1 12 Gauge 18.5″ Threaded 6+1 Black
About this product
The Mossberg 590A1 12 Gauge 18.5″ Threaded 6+1 Black is a mil-spec pump-action shotgun built to military standards for duty and security applications. Its heavy-walled barrel, optic-ready receiver, and M-LOK compatible forend make it one of the most durable and customizable defensive shotguns on the market. This platform has been proven in military service and law enforcement roles where reliability under stress matters more than aesthetics.
What is the Mossberg 590A1 used for?
The Mossberg 590A1 is designed for duty, security, and home defense applications where absolute reliability is non-negotiable. Its 18.5-inch heavy-walled barrel withstands sustained firing without warping, while the 6+1 capacity provides practical ammunition management without excessive bulk. The threaded barrel accepts chokes or suppressors, and the M-LOK forend allows for light or laser mounting exactly where you need it.
How does the Mossberg 590A1 compare to the Stevens 555 Sporting O/U 12 Gauge?
The Mossberg 590A1 outperforms the Stevens 555 Sporting O/U in reliability and customization for defensive use, while the Stevens excels at clay shooting and hunting. The 590A1's pump action cycles reliably even with low-power loads and dirty conditions, whereas the Stevens 555's over-under action requires cleaner ammunition and more maintenance. For home defense or duty use, the 590A1's 6+1 capacity and accessory mounting options make it superior to the Stevens' two-round limit and traditional stock.
What does it weigh and what are the dimensions?
The Mossberg 590A1 weighs 7.25 pounds unloaded and measures 39.5 inches in overall length. The 18.5-inch barrel contributes significantly to the weight distribution, making it feel balanced during rapid handling drills. At 7.25 pounds, it's heavier than many sporting shotguns like the Stevens 555 Sporting 20 Gauge but lighter than full-length riot guns with extended magazines.
Who is this NOT for?
The Mossberg 590A1 is not suitable for hunters or recreational shooters who prioritize light weight and fast handling. At 7.25 pounds, it's significantly heavier than field models like the Stevens 334 Rifle in .308 Win, and its tactical features add bulk without benefiting hunting scenarios. If you need a shotgun for upland birds or clays, consider the Stevens 555 Sporting O/U instead.
What's in the box?
The box includes the Mossberg 590A1 shotgun, one Accu-Choke Cylinder Bore choke tube, a receiver optic cover plate, and owner's manual. You'll need to purchase ammunition, cleaning equipment, and any optics separately—the Shield RMSc footprint requires specific micro red dots that aren't included. The choke tube is pre-installed but requires periodic maintenance to prevent carbon locking.
Is the Mossberg 590A1 worth it at $714.99?
At $714.99, the Mossberg 590A1 delivers exceptional value for a mil-spec shotgun with threaded barrel and optic-ready features. Compared to custom-built alternatives that start at $1,200+, the 590A1 includes critical upgrades like heavy-walled barrel and M-LOK mounting out of the box. For serious defensive use where reliability matters more than cost, this platform justifies its price with proven military adoption and rugged construction.
Specs at a glance
Video review
Pros & cons
What works
- Heavy-walled 18.5-inch barrel withstands sustained fire without warping
- Optic-ready receiver with Shield RMSc footprint accepts micro red dots without adapters
- M-LOK forend provides 8 mounting slots for lights and accessories
- 6+1 capacity balances firepower with manageable size at 39.5 inches overall
Trade-offs
- Weighs 7.25 pounds—2.5 pounds heavier than field shotguns like Stevens 555
- Parkerized finish requires frequent oiling to prevent rust in humid conditions
- Synthetic stock lacks adjustable comb or length-of-pull spacers included
Expert review
Key attributes
| upc | 015813507998 |
| manufacturer | Mossberg |
| manufacturer part number | 50799 |
| action | Pump Action |
| barrel length | 18.50" |
| caliber/gauge | 12 Gauge |
| capacity | 6 + 1 |
| chokes included | Cylinder |
| sights | Bead Front |
Frequently asked questions
- Is it compatible with suppressors?
- Yes, the Mossberg 590A1's threaded barrel accepts standard 12 gauge suppressors with appropriate mounting systems. The threads are cut to SAE specifications, compatible with most major suppressor brands like SilencerCo and Dead Air. Always verify thread pitch (typically ¾-24) and use a bore-specific suppressor rated for 12 gauge pressures.
- Does it fit in a standard gun safe?
- The Mossberg 590A1 requires a safe with at least 40 inches of interior length to accommodate its 39.5-inch overall length. Most 10-gun safes with 42-inch interiors will fit it comfortably alongside rifles like the Stevens 334 .308 Win. Consider vertical storage or angled racks if space is limited.
- How long does shipping take?
- Shipping typically takes 3-5 business days for in-stock items, plus FFL processing time which varies by location. All firearms ship via FedEx or UPS with adult signature required upon delivery. Your FFL will contact you when the firearm arrives for background check and transfer.
- Can I return it if it doesn't fit?
- Firearms sales are final once transferred through an FFL, unless there is a manufacturer defect. Ironclad Armory inspects all firearms before shipment and provides a 30-day warranty against defects. If the shotgun doesn't fit your intended use, consider consulting our experts before purchase.
- Does this work with Benelli M4 accessories?
- No, the Mossberg 590A1 uses proprietary forend and stock mounting systems incompatible with Benelli M4 accessories. The M-LOK forend accepts standard M-LOK accessories, but stock adapters and magazine tubes require Mossberg-specific parts. Always verify compatibility with Mossberg 500/590 series before purchasing accessories.