I have to say I am shocked that you would question whether the "public" has a right to know what ammo is used by various civilian police agencies. Have we really come so far in our culture of "us" and "them" that police or non-LE taxpayers would think such information to be "classified?" It is not like we are talking nuclear launch codes here.

The answer is that the types of ammo used varies as much as the types of fire arms used. It also varies by whether officers are required to purchase their own or whether the agency buys it for the officers.

The ammo used by the larger agencies is generally known, but changes from time to time, so information that is generally out may not still be accurate, so I will give you what I last saw reported for a few agencies, at least to the best of my recollection.

St. Louis Metropolitan Police uses a 147 grain 9mm JHP made by Winchester.

FBI uses a white box packaged PDX1 load marked on the boxes as merely a bonded hollow point made by Winchester, .40 S&W caliber, 180 grain.

NYPD uses the Speer Gold Dot 124 grain JHP +P in 9mm. To the extent they still allow revolvers, their ammo is the Speer Gold Dot Short barrel 38 Special ammo.

Secret Service uses .357 SIG JHP ammo, but not sure of manufacturer.

I cannot really recall other agencies right now.