The PX4 Storm Special Duty in .45 ACP was Beretta's entry in the 2005 USSOCOM Joint Combat Pistol trial.
Came from the factory with an extended 4.5 inch barre. It was originally for the ability to mount a suppressor. But Beretta, wanting to keep it legal in as many markets as possible, didn't thread the commercial released barrel.
Beretta showing off one of the JCP trial gus at the 2011 NDIA Infantry Small Arms Systems Symposium. It was converted to a "D" setup, as a DAO gun.
I ordered a regular 4 inch barrel for it since I don't ever intend to suppress the gun.
You can change it from a safety/decocker "F" gun to a decocker only "G" but just removing a ball bearing in the safety.
I got mine used, paid far less than what they go for back in 2018. It is a great shooter.