The Sig Sauer P320 M18X is a striker-fired 9mm pistol with a 3.9-inch barrel, 21+1 capacity, and Siglite night sights front and rear. The finish is Coyote PVD with a coyote polymer grip. It shares the M18 military specification platform. 
 

Key Specifications 

• Manufacturer: Sig Sauer 
• Model: P320 M18X 
• Action: Semi-Automatic (Striker Fired) 
• Caliber: 9MM Luger (9x19 Para) 
• Barrel Length: 3.9 inches 
• Overall Length: 7.2 inches 
• Capacity: 21 Rounds (+1) 
• Weight: 1.9 lbs (30.8 oz) 
• Finish: Coyote PVD (Coyote Tan Carbon) 
• Grip Material: Coyote Polymer 
• Sights: Siglite Front and Rear Night Sights 
   

Detailed Features 

 
The P320 platform uses a serialized fire control unit that can move between different grip modules and slides, making it interchangeable with other P320 variants. At 21+1 rounds, the M18X has higher capacity than most duty-size striker-fired pistols. Siglite night sights are standard on both front and rear. 
 
The coyote tan finish and grip give it a different look from standard black pistols. The striker-fired action provides a consistent trigger pull shot to shot.

The P320 M18X generates positive feedback on ergonomics -- most shooters find the grip comfortable and easy to control at speed. The platform's modularity is a frequently discussed feature; swapping frames, slides, and calibers appeals to owners who want flexibility.

Accuracy is consistently rated well across distances, and the 21-round capacity is appreciated. The Siglite night sights are called out as a useful standard feature. Trigger feel is where opinions split -- many like it, but some find it less crisp than their preferences. At 30.8 oz. the M18X is on the heavier side for a concealed carry option, and that trade-off with the higher capacity is a recurring discussion. Price also factors in for some buyers.