Whenever someone who wants our guns banned speaks, they always get around to how they are for criminals, militia nuts, or general malcontents and that legitimate gun owners and sportsmen don't need them and don't want them. Obviously, that's not true.
A way to counter this is to equate these guns with modern firearms, which is exactly what they are. When the question is posed as to why you need them, simply state that the are the latest in state of the art firearms, and that you have no interest in buying 100 year old designs (revolvers, bolt actions, lever actions, etc). After all, you wouldn't buy an 8 track tape player today, would you? Basically, the anti AW crowd wants to freeze civilian firearm technology to 1937. That wouldn't work with any other category of material good, but they make it work with modern firarms because they have successfuly equated modern designs with antisocial behavior and use the guilt of consideration of a purchase as a dererrant. Want an AR, you are bad! Want a 1894 Win, you are good!
I am a gun collector, because I enjoy all guns, but my Mausers, Enfields, and Mosins are obsolete designs, and are inferior to modern stuff. Why should we gun owners be forced into feeling guilty because we want to obtain and use modern firearms. I use this argument fairly often, and in some cases it does 'disarm' an opponent whose primary attact is a 'Why would a legitimate gun owner want those' attack.