How does section 654 of the California Criminal Code apply to a firearm possession charge where all the ammunition is loaded into the firearm?

"An act or omission that is punishable in different ways by different provisions of law shall be punished under the provision that provides for the longest potential term of imprisonment, but in no case shall the act or omission be punished under more than one provision." ( 654, subd. (a).) Where, as here, all the unlawfully possessed ammunition is loaded into the unlawfully possessed firearm, section 654 prohibits multiple punishment for the two crimes. (People v. Lopez (2004) 119 Cal.App.4th 132, 137-139.) "[R]ather than dismissing charges or imposing concurrent sentences, when a court determines that a conviction falls within the meaning of section 654, it is necessary to impose sentence but to stay the execution of the duplicative sentence . . . . [Citations.]" (People v. Duff (2010) 50 Cal.4th 787, 796.) Thus the sentence must be modified accordingly.