A thought on shooting down missiles, I don't remember where to find a link on this anymore, but about a year ago someone was entering the testing stages on a type of gum designed to saturate a 3/4 m x 3/4 m or 1/2 m by 1/2 m area with bullets. It uses a array a parallel barrels that are mounted about 3-6 cm from centers (rather uncertain on this exact distance), and utilizes caseless rounds to attain an increased rate of fire over standard ammunition. If I remember correctly the idea behind this was that you would try to get a 1-3 or second window in which the missile had to pass certain point, and fire into that area. The rate of fire would practically guarantee a hit on most passing objects, I haven't heard any reports on the success of this device against any actual missiles though, trials had not started at the time the article I read reached print. This would use a large amount of ammunition, but would increase the chances of hitting the missile over a standard single barrel system.
In terms guns in 2064, this could be refined into a useful system, reducing the TN to hit an incoming missile far enough to make it possible. As you can guess this would required a fairly large platform to handle the recoil, and with something in the range of a 10 x 10 array of barrells anything caught in this kind of full auto fire would suffer, I don't know how to stat this out for the can yet, but it could see some use in a higher end game.
A random thought for the day.