well to be fair the game don′t need to follow realism like a slave, it is a 10mm, it has a silencer on it and thus is silent. Don′t need to be more complicated then that, to be frank I don′t see the need for a specific sub-sonic ammo in the game, seam just like one more type of ammo to keep track of in return for having just a tiny slice of realism to the game.