One way to go about owning a modern semi-automatic sporting rifle in California starting Jan 1 2017 is to buy/build them ‘featureless’. What this means is you take away any ‘evil feature’ per California standards. Features include a pistol grip, bullet button, flash hider, collapsable or folding stock and forward vertical pistol grip.
Once this is achieved you are legal to have an original push button magazine release from the factory. If you’re having a hard time picturing all of this as a whole try thinking about the Ruger Min-14, Springfield Armory M1A or an M1 Carbine… all of these are legal under California law and all are considered featureless.