Sure departments have switched from Beretta to other brands - and the opposite is true. Not all departments stayed with Glock either. How many different issue guns has the FBI used in the last 30 years?
But the big agencies, especially ones like the Border Patrol which has a fair amount of combat, choose based on some practical criteria too.
But the big agencies, especially ones like the Border Patrol which has a fair amount of combat, choose based on some practical criteria too.