The FN SLP is a semi-automatic 12-gauge from FN America built around an active valve gas system that handles a wide variety of loads — from light target rounds to heavy buckshot — without adjustment. The 18-inch barrel, 6+1 extended tube, and ghost ring sights position it squarely for home defense and competition use. 
 

Key Specifications 

• Manufacturer: FN America 
• Model: SLP 
• GSIN: FNMRC-XWG6BPC8 
• Caliber: 12 Gauge 
• Barrel Length: 18 inches 
• Chamber Size: 3 inches 
• Magazine Capacity: 6+1 rounds (extended tube) 
• Weight: 7.7 lbs (125 oz) 
• Total Length: 38.75 inches 
   

Detailed Features 

 
The active valve gas system is the core of the SLP's load versatility — it self-regulates to cycle everything from 2.75-inch light loads to 3-inch magnums. The high-profile adjustable ghost ring rear sight pairs with a wing-protected blade front sight, giving a precise picture for defensive or competition work. The aluminum alloy receiver keeps overall weight at 7.7 pounds despite the steel barrel. A fixed synthetic stock with rubber butt plate handles recoil well during extended shooting. The 38.75-inch overall length with an 18-inch barrel is maneuverable in tight spaces.

The FN SLP gets positive marks for reliability and load versatility. Owners who run it in 3-Gun or similar competitions appreciate that it cycles different ammunition types without fuss. Build quality and the adjustable ghost ring sights get consistent praise.

Price is a common discussion point — the SLP sits higher than many comparable semi-auto defensive shotguns, so buyers tend to weigh features against cost carefully. New shooters transitioning from pump to semi-auto occasionally mention a break-in period, but most find the operation intuitive once familiar with it.