The Sig Sauer P320 Pro is a striker-fired semi-automatic pistol chambered in 9mm with a 3.9-inch barrel. It ships with a 17-round magazine, X-Ray 3 tritium night sights, and a Romeo-X optic footprint. The Nitron black finish covers the slide over a polymer grip module. 
 

Key Specifications 

• Brand: Sig Sauer 
• Model: P320 
• Caliber: 9mm 
• Action: Semi Auto 
• Barrel Length: 3.9 in 
• Capacity: 17 rounds 
• Color/Finish: Black 
   

Detailed Features 

• 3.9-inch barrel in the compact Pro configuration 
• 17-round magazine capacity 
• X-Ray 3 tritium night sights 
• Romeo-X optic-ready footprint 
• Polymer grip module

Owners who chose the P320 Pro specifically for the Romeo-X optic footprint say it is the main differentiator over the standard compact configuration. The 17-round capacity in the same compact frame as the 15-round variant is a notable draw, and most owners find the extra two rounds worth having without a noticeable change in size.

The X-Ray 3 night sights are well regarded as a backup iron option even when running a dot. Owners generally report that the sights co-witness usefully with the Romeo-X and that the combination works out of the box without additional fitting.

The Pro designation gets discussed in owner forums largely around trigger feel. Some owners find the Pro-tuned trigger a noticeable step up from the base P320, while others say the difference is marginal. Reliability is broadly positive across the owner base, with the P320 platform's established track record carrying over to this configuration.