John Reese, is a highly trained ex - CIA operative working with Harold who is a billionaire. He can buy all kinds of weapons as we have seen.
But I noticed that he never uses a silencer for any of his pistols. He usually shoots in places which have a high number of people who can listen to the shots. Wouldn't it make more sense to use a silencer?
All his enemies aka assassins use them. So why doesn't he ?