FN 57 Magazine 10rd Extension Kit

FN Five-seveN Mag Extension

The CMMG FN 57 Magazine 10rd Extension Kit turns a factory 20-round FN Five-seveN magazine into a 30-round magazine. It replaces the factory floor plate and spring with a longer polymer extension and a matching spring, so you get more 5.7x28mm rounds per reload from magazines you already own. It suits Five-seveN shooters who want more capacity at the range or in a home-defense setup without buying a separate extended magazine.

Features

• Adds 10 Rounds — Fitting the kit to a factory 20-round magazine raises total capacity to 30 rounds.
• 5.7x28mm Caliber — Built for the small, high-velocity bottlenecked cartridge the FN Five-seveN pistol fires.
• Polymer Extension Body — The black polymer housing extends the bottom of the magazine to make room for the extra rounds.
• Chrome Silicon Wire Spring — The longer replacement spring is wound from chrome silicon wire and resists salt water corrosion.
• Will Not Take A Set — The spring holds its tension when the magazine stays loaded, rather than shortening and weakening over time.
• Drop-In Installation — Remove the factory floor plate, fit the extension and new spring, and the magazine is ready to load.
• No Permanent Alteration — The factory magazine body is not cut or modified, so you can return it to stock form.
• Factory-Matched Contour — The extension follows the shape of the original Five-seveN magazine for a consistent profile.
• Gen1 Magazine Fit — Designed for first-generation FN Five-seveN magazines and not compatible with the newest magazine designs.

Fit And Installation

The kit works with factory FN Five-seveN Gen1 20-round magazines, so check your magazine generation before ordering, because it will not fit the latest designs. Installation needs no gunsmithing: the factory floor plate comes off, and the polymer extension and chrome silicon spring take the place of the originals. The kit is CMMG part number 57AFD1E.