Warne Magazine Extension for S&W M&P 9mm/40 S&W +5/+4 Black

The Warne Magazine Extension increases capacity on factory Smith & Wesson M&P magazines by 5 rounds in 9mm or 4 rounds in 40 S&W. Designed for competitive shooters and range use where extended capacity provides a tactical advantage, this extension maintains reliable feeding while adding extra rounds without requiring a new magazine body.

Machined from aluminum with a black anodized finish, the extension replaces the factory magazine baseplate with a drop-in installation—no gunsmithing or permanent modifications required. The included extension spring ensures proper magazine function with the added capacity. Note that use of this extension may make the magazine non-compliant in jurisdictions with magazine capacity restrictions.

• Part Type: Magazine Extension
• Compatible Firearms: Smith & Wesson M&P 9mm and 40 S&W
• Capacity Increase: +5 rounds (9mm), +4 rounds (40 S&W)
• Material: Aluminum
• Finish: Black Anodized
• Installation: Drop-In
• Includes: Extension body, extension spring