Sig Sauer builds this factory extended magazine (part no. MAG-MOD-F-43-18) for the full-size P320 and P250, holding 18 rounds in a blued metal body sized for both .40 S&W and .357 SIG. As the highest-capacity option in Sig’s .40/.357 SIG lineup for these platforms, it gives shooters extended reserve capacity for range use or a duty spare without switching to a different caliber altogether. Manufactured to Sig’s own factory tolerances, it feeds and seats exactly as intended. For Sig Sauer P320 and P250 owners, this handgun magazine is a dependable high-capacity spare.

Key Specifications

• Chambered for .40 S&W and .357 SIG, sharing one magazine geometry.
• Holds 18 rounds, an extended high-capacity option for the platform.
• Fits the Sig Sauer P320 and P250 full-size frames.

Frequently Asked Questions

Does one magazine work for both .40 S&W and .357 SIG? Yes, both cartridges share the same case head dimensions and run through this same magazine.

Is this a genuine Sig Sauer factory magazine? Yes, manufactured by Sig Sauer to full-size P320/P250 specifications.

Buy the Sig Sauer P320/P250 18-Round .40 S&W/.357 SIG Magazine

A high-capacity factory spare keeps a P320 or P250 topped off for the range. Order it from our Lubbock, Texas gun shop for fast, insured shipping.