FN 509 Midsize 24-Round 9mm Magazine Sleeve - Extended Capacity

The FN 20100356 Magazine Sleeve transforms the FN 509 Midsize into a higher-capacity platform without compromising the pistol's balanced handling characteristics. This factory-engineered sleeve extends magazine capacity to 24 rounds of 9mm Luger ammunition while maintaining the reliability standards expected from FN Herstal.

What Makes This Different

Unlike aftermarket extensions that can affect feeding reliability, this FN factory sleeve integrates seamlessly with the 509 Midsize frame geometry. The sleeve maintains proper spring tension across the extended capacity range and preserves the magazine's drop-free function. Factory engineering ensures consistent feeding with various 9mm ammunition weights and profiles.

Key Features

• Extends capacity from standard 15 rounds to 24 rounds of 9mm Luger
• Factory-manufactured sleeve designed specifically for FN 509 Midsize pistols
• Maintains original magazine body integrity and spring specifications
• Compatible with existing FN 509 Midsize holsters when magazine is seated
• Polymer construction matches FN factory magazine materials
• Preserves magazine's anti-tilt follower design
• Retains witness holes for round count verification

The extended capacity proves valuable in competitive shooting disciplines where higher round counts reduce reload frequency. Law enforcement professionals appreciate the additional ammunition capacity during extended engagements. The sleeve adds minimal length to the magazine while providing substantial capacity increase, making it practical for duty carry applications where extended magazines are authorized.

Technical Specs

• Capacity: 24 rounds of 9mm Luger ammunition
• Compatibility: FN 509 Midsize pistols exclusively
• Material: High-impact polymer construction
• Finish: Black polymer matching FN factory specifications
• Spring: Factory-tuned for 24-round capacity
• Follower: Anti-tilt design with witness holes
• Manufacturer: FN Herstal (Belgium)
• Model Number: 20100356

This factory sleeve represents the most reliable method for increasing FN 509 Midsize capacity without compromising the platform's inherent reliability. Professional users who require extended capacity will find this sleeve delivers consistent performance across thousands of rounds.