Franklin Armoy’s Drop-In Fixed Magazine is a great affordable way to be 2017 California Compliant. This magazine can only be installed when the rear takedown pin is pulled and the action is open. It only drops in from the top.
In order to drop it in, you must remove your factory bolt catch, drop the magazine in, then re-install your bolt catch. This will create a fixed magazine and your magazine release button will be useless, at this point.
NOTE: If you want to easily insert and remove your Franklin Drop-In Fixed Magazine, then you will want to install the Franklin DFM Bolt Catch. See Below.