The Sig Sauer P320 Full OR is a striker-fired semi-automatic pistol in 9mm Luger with a 4.7-inch barrel, a PRO optic footprint for red dot mounting, and SIGLite night sights. The modular design lets users swap frames, grips, and barrel configurations without tools. 
 

Key Specifications 

• Brand: Sig Sauer 
• Model Name: P320 Full OR 
• Caliber: 9mm Luger 
• Action Type: Striker Fired 
• Capacity: 10 + 1 Rounds 
• Barrel Length: 4.7 inches 
• Sights: SIGLite Front & Rear Night Sights 
• Grip Material: Black Polymer 
• Weight: 29.4 oz (1.84 lbs) 
• Finish: Nitron Black 
• Condition: New in Box 
   

Detailed Features 

The PRO optic footprint on the slide accepts common red dot sights directly, removing the need for adapter plates. SIGLite tritium night sights come installed from the factory, so the gun is usable in low light out of the box. 
 
The carbon steel barrel has a DLC (Diamond Like Carbon) coating for wear resistance. Interchangeable polymer grips in multiple sizes let the shooter fit the gun to their hand. A full-length accessory rail under the barrel accepts lights and lasers. 
 
The modular FCU (Fire Control Unit) is the serialized component, meaning frames, slides, and barrels can be swapped to change caliber or configuration without separate transfers.

The P320 OR gets broadly positive marks, with discussion concentrated around a handful of topics.

Modularity is the feature most praised. Users appreciate being able to swap frames and slides, and the optics-ready cut gets mentioned frequently by anyone who runs a red dot or plans to.

Ergonomics and grip come up consistently. Most shooters find the grip angle and texture comfortable for extended range sessions. Fit-to-hand tends to be the first thing people mention when they shoot it for the first time.

Accuracy reviews are positive across defensive and target shooting uses. Night sights are considered a genuine plus for anyone who trains or carries in varied lighting.

Reliability holds up well in most accounts, with very few reports of malfunctions after extended use.

Trigger feel divides opinion. Some owners find it smooth and consistent; others would prefer a lighter break. It's a common enough complaint that aftermarket trigger upgrades for the P320 are widely available.

Size is noted as a consideration for concealed carry. The full-size OR is not a small gun at 29.4 oz., and a few reviewers mention preferring the compact variant for carry while keeping the full-size for home and range use.

Price relative to competing 9mm pistols draws some comment. The P320 generally sits at the higher end of the market, and not everyone agrees the premium is justified compared to alternatives.