SIG SAUER P320/P250 Full-Size 21-Round 9mm Magazine

SIG SAUER P320/P250 Full-Size 21-Round 9mm Magazine

Add useful range capacity or keep a factory spare available with this SIG SAUER 21-round extended magazine. The magazine is chambered for 9mm Luger, finished in black, and identified by SIG SAUER part number MAG-MOD-F-9-21 and UPC 798681555253. Its extended configuration provides four additional rounds compared with a standard 17-round full-size magazine.

This is an original SIG SAUER magazine designed around the company’s modular full-size and carry pistol platforms. SIG’s current compatibility list includes the P320, P250, M17, M18, P211-GTO, P211-GT4, and P211-GT5. Because grip modules, magazine baseplates, and model generations can vary, confirm the exact pistol and grip configuration before ordering.

Key Features

• Capacity: 21 rounds
• Caliber: 9mm Luger
• Configuration: Extended full-size/carry magazine
• Color: Black
• Compatible families: P320, P250, M17, M18, and compatible P211 models listed by SIG SAUER
• Manufacturer part number: MAG-MOD-F-9-21
• UPC: 798681555253
• Quantity: One magazine

Factory Fit for Training and Spares

A quality spare magazine is one of the most practical additions to a pistol setup. Extra magazines reduce downtime during training, make it easier to separate practice ammunition from other loads, and allow worn or damaged magazines to be removed from service without interrupting a range session. The 21-round capacity is particularly useful for high-volume practice and for owners who want the same extended format commonly associated with SIG’s full-size duty-oriented pistols.

The extended base area projects below a compatible grip module, making the magazine easier to identify and grasp during reloads. The black finish provides a neutral appearance that pairs naturally with black P320 and P250 grip modules while remaining suitable for other compatible finishes.

Compatibility and Maintenance

Use this magazine only with compatible 9mm SIG SAUER pistols. Do not rely on the shared P320/P250 family name alone: compact and subcompact grip modules may have different fit considerations, and aftermarket magwells or modified baseplates can affect seating. Compare the part number, caliber, capacity, and your firearm’s configuration before use.

Before loading, inspect the magazine body, feed lips, follower, spring function, and baseplate. Keep the magazine clean and dry, and follow SIG SAUER’s instructions if disassembly is required. With the firearm unloaded, confirm that the magazine locks securely, releases normally, and does not interfere with the grip module or magwell. Function-test every magazine with the ammunition you intend to use.

Magazine-capacity restrictions vary by state and locality. Verify that a 21-round magazine may be purchased, shipped, possessed, and used in your jurisdiction before ordering.