I have no shooting experience, but the arc they have to put into the shot to travel 4.4 miles (~7 km), seems so counter-intuitive to what I associate with shooting. Really impressive work by this team, to have all this calculated out so that they can hit it within 69 shots.
I'm really curious what the success rate of their shot is. From the video, it sounds like the unsuccessful shots were still relatively close by, enough that they seemed confident in being able to still guide it in, so around 1/100 sounds about right, as a crude prior estimate.