The Orthos Arms Raider S4 is a semi-automatic shotgun chambered in 12 gauge with an 18.5-inch barrel and a 3-inch chamber. It has a 6+1 round capacity, an M-LOK compatible handguard, and a Flat Dark Earth stock and finish throughout. 
 

Key Specifications 

• Brand: Orthos Arms 
• Model: Raider S4 
• Caliber: 12 Gauge 
• Action: Semi Auto 
• Capacity: 6+1 rounds 
• Barrel Length: 18.5 in 
• Color/Finish: FDE (Flat Dark Earth) 
   

Detailed Features 

• 18.5-inch barrel with 3-inch chamber 
• 6+1 round capacity 
• M-LOK handguard 
• Flat Dark Earth stock and furniture 
• Tactical semi-auto configuration

Owners drawn to the Raider S4 typically want a home-defense or duty-style shotgun in a non-standard color. The FDE finish and M-LOK handguard give it a modern tactical look, and the 18.5-inch barrel keeps it maneuverable. Initial reliability reports on the semi-auto action are generally positive with standard 2.75-inch and 3-inch loads, though some owners recommend running a break-in round count before relying on it.

The 6+1 capacity is seen as adequate for its intended role, and the M-LOK rail positions allow for lights or foregrips without a separate adapter. Ergonomics are described as comfortable by most owners, though the Flat Dark Earth stock dimensions do not adjust, which can be a fit issue for shooters at the taller or shorter ends of the range.

Orthos Arms is a smaller brand and aftermarket support is limited compared to the major names in semi-auto shotguns. Buyers report reasonable value for the price, but those with a specific accessory upgrade path in mind may find sourcing parts less straightforward. Customer service feedback is mixed and mostly anecdotal at this stage.