SIG SAUER P320 Full-Size 18-Round .40 S&W/.357 SIG Magazine

The SIG SAUER MAG-MOD-F-43-18 is a factory 18-round magazine for full-size P320 pistols chambered in .40 S&W or .357 SIG. It gives owners a genuine SIG magazine for range use, training, or replacement of an existing magazine while keeping the fit and operating geometry specified for the platform. SIG lists this exact part as a full-size P320 magazine in both calibers.

Factory P320 fit

This is a caliber-specific, full-size magazine rather than a universal P320 component. It is intended for compatible full-size P320 configurations in .40 S&W or .357 SIG. Because the P320 family includes multiple frame sizes, generations, and caliber arrangements, confirm your pistol’s chambering and grip-module size before ordering. The part number on the package should read MAG-MOD-F-43-18.

18-round capacity

The magazine holds 18 cartridges, providing higher capacity than standard flush-fit .40 S&W and .357 SIG magazines. Its extended configuration is useful for range sessions and training where additional capacity is desired. The black exterior maintains a factory appearance and pairs naturally with standard black P320 components.

Product details

• Manufacturer: SIG SAUER
• Manufacturer part number: MAG-MOD-F-43-18
• UPC: 798681561018
• Platform: Full-size SIG SAUER P320
• Calibers: .40 S&W and .357 SIG
• Capacity: 18 rounds
• Color: Black
• Type: Detachable pistol magazine
• Quantity: One magazine

Choosing the correct magazine

Use the manufacturer part number—not appearance alone—to verify compatibility. Similar P320 magazines are offered for other calibers, capacities, and grip-module sizes, and those variants are not interchangeable in every configuration. If your pistol has been converted between calibers or uses a nonstandard grip module, consult SIG SAUER documentation or a qualified armorer before use.

Observe all applicable magazine-capacity laws and restrictions. Before loading, inspect the magazine and pistol, follow the firearm manufacturer’s instructions, and discontinue use if either component shows damage or unusual wear.