1. Depress the button on the bottom of the magazine and slide the basepad all the way off of the magazine tube.
2. If using the Grams spring and follower, remove the factory spring and follower and insert the Grams spring and follower into the magazine tube, ensuring the front of the follower is pointing towards the front of the magazine tube. If using the factory spring and follower, remove the locking plate (plastic tab) at the bottom of the spring while keeping the follower and spring in the magazine tube.
3. Hold the magazine upside down, bullets forward, and compress the spring with your thumb until the spring is level with or slightly below the bottom of the magazine tube. Using your free hand, begin to slide the extension on the bottom of the magazine tube.
4. If you are concerned with scuffing the lock or the anodizing, ensure the bottom coil is pushed down enough to clear the back edge of the extension.
5. Continue sliding the extension onto the tube until the lock on the extension pops up behind the magazine tube.
6. Push down the follower to ensure the bottom of the spring is fully seated in the extension.
