Do police officers buy and choose their own firearms And can they choose what breed of dog to buy as their K9 officer if approved?

I don't know about the K9 question, but in regards to firearms, it depends on the local PD policy. Where I live, all officers carry department issued weapons. There are no options. The gun is a Sig 229M and I think the shotgun is a Winchester. Some cities issue weapons but have more than one option. Most larger cities issue guns, but in some smaller cities, officers buy their own handguns from a list of approved models. In some really small cities, officers can carry anything they want to buy. n Shiz