ProMag SIGA4 20rd Magazine for Sig Sauer P226 (.40 S&W/.357 Sig)

The ProMag SIGA4 is a 20-round replacement magazine designed for use with the Sig Sauer P226 in .40 S&W and .357 Sig. It features a steel body construction with polymer components where appropriate and a heat-treated spring for consistent feeding. The magazine is intended as an extended-capacity option for range use, competition, or recreational shooting. Compatibility and basic materials are drawn from manufacturer-provided specifications.

Key Specifications

• Compatible with the Sig Sauer P226 and chamberings 40 S&W/357 Sig.
• The capacity is 20 rounds.
• Constructed with a steel body for structural strength.
• The follower lock-plate and base-plate are molded from a DuPont Zytel-based black polymer.
• The spring is wound from chrome-silicon wire and heat-treated for durability.
• Designed as an extended 20-round magazine for increased capacity options.
• Finish information is not included here due to inconsistent source data; see notes.

This SIGA4 magazine offers a straightforward, mechanically focused solution for shooters seeking a higher-capacity option for the P226 platform. With a steel body, polymer components in wear areas, and a heat-treated chrome-silicon spring, it is built to the basic functional needs of range and competitive use while maintaining reliable feeding characteristics.