ProMag builds this magazine (part no. SIG-A20) as a replacement or spare for the Sig Sauer P320, chambered in 9mm Luger. The body is heat-treated steel finished in blue, with an injection-molded follower and a spring formed from chrome silicone wire, and it’s assembled in the USA. Holding 21 rounds, it’s a high-capacity option above the P320’s standard factory magazine. For ProMag owners running a P320, this handgun magazine adds a lot of rounds on tap.

Key Specifications

• Chambered in 9mm Luger.
• Holds 21 rounds, a high-capacity option for the platform.
• Fits the Sig Sauer P320.
• Built from heat-treated steel, finished in blue.
• Uses an injection-molded follower and a chrome silicone wire spring.
• Assembled in the USA.
• Carries the manufacturer’s Standard model designation.
• Classified by the manufacturer as Accessory-Magazines.
• Weighs approximately 0.25 lb as shipped.
• Measures approximately 6 inches in overall length.
• Ships in a compact retail box, roughly 1.4 by 4.6 inches.

Frequently Asked Questions

What pistol does this fit? The Sig Sauer P320, chambered in 9mm Luger.

How many rounds does it hold? 21 rounds, above the P320’s standard factory capacity.

Buy the ProMag Sig P320 21-Round Magazine

A high-capacity blued-steel spare, this ProMag magazine adds a lot of rounds on tap for your P320. Order it from our Lubbock, Texas gun shop for fast, insured shipping.