Below are step-by-step instructions for installing the Apex J-Plate Base Pad for the Magpul GL9 PMAG. If after reading these instructions you still have questions, please contact Apex Customer Service at (805) 528-5250.


Always wear safety glasses when working on firearms. We recommend this product be installed by a competent gunsmith. Modification of your firearm may nullify the warranty of the firearm manufacturer.

Recommended Tools

  • Pin Punch
Apex 102-135-1

Installation Procedure

  • Remove magazine and make sure firearm is unloaded and in a safe condition
  • Take your empty Magpul PM9 series magazine and remove the base pad by pressing the base pad retainer with a punch or other tool and sliding the base pad rearward
  • When removing the base pad, be sure to capture the spring and retainer with your hand so it does not fly across your work area
  • Install the Apex J Plate by compressing the spring and sliding it into the magazine from the rear to the front
  • The base pad should click into place when installed properly
  • Check installation by pushing on the front of the J plate. It should not slide off