You're browsing the GameFAQs Message Boards as a guest. Sign Up for free (or Log In if you already have an account) to be able to post messages, change how messages are displayed, and view media in posts.
It's completely variable based on accuracy and distance to target. There's no magic number of seconds it takes. If I'm point blank loading someone's face with AR and they aren't moving, it's gonna be quite short, but that's not exactly gonna be very helpful in online combat, is it?