Eh. Just judge for yourself. Some choice excerpts:
The basics on magazines: they are attached into a particular type of gun to provide an individual with a certain number of bullets without having to reload. A pistol, like the one I own, only has 5 in the chamber and does not use a magazine.
Just as we're not able to have certain type of bullets or silencers for safety reasons, high capacity magazines need to fall into this same category. One possible consensus - maybe we can propose that high capacity magazines are treated the same way as silencers/suppressors - if your state allows them (only 38 of the 50 do), you have to go through the Bureau of Alcohol, Tobacco and Firearms to register for silencer ownership and have it registered. It doesn't mean that you can't have one in your gun collection - it's just registered through the ATF.
Clearly the opinion of someone who knows nothing about the NFA process or someone who knows about and simply has nefarious intent.