The Beretta PX4 Storm uses specific magazines depending on its frame size.
Full-Size PX4 Storm:
- 9mm models have a 17-round standard capacity
- .40 S&W models have a 14-round standard capacity.
Compact PX4 Storm:
- 9mm models have a 15-round standard capacity
- .40 S&W models have a 12-round standard capacity.